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Alan-Cox opened this issue Jan 25, 2012 · 9 comments
Closed

Architecture Code #6

Alan-Cox opened this issue Jan 25, 2012 · 9 comments

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@Alan-Cox
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This will need splitting up - eg big chunks of it are for the USB driver and that is probably a "no hope" item in itself.

  1. Platform code references stuff that doesn't seem PI relevant or included (eg touchscreen)
  2. Minor style stuff - usual plus strip out LINUX_VERSION_CODE checks when upstreaming
  3. DMA manager - you assume there is only one, so you should check that in bcm_dmaman_probe()
  4. General - bound to get asked if you can not use devicetree for all the device and IRQ description rather than yet more platform files.
  5. Some bits (eg pcm_power) need a fairly serious revisit and exposing via the properly kernel power interfaces eventually. Also lose the semaphores for mutexes as they are not counting. Otherwise you muck up real time.
  6. vc_mem.c - LOG_xxx crap - and in general a nop hoper that needs major work (so again best split out)
  7. MMC - split this off because it needs major work to get anywhere upstream and probably to be done in small steps beginning with PIO. For MMC I think a lot of it may well look better as of 3.2 because MMC/SDHC now has a proper power infrastructure

For this I think you've got a good chance of getting the various quirks, basic board bits upstream easily. A lot of the other more driver-ish stuff is going to need stuff addressing.

@Alan-Cox
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Oh a ps vc_ is the symbol space used for the virtual console code so you want to move from vc_ to something else (bcmvc_ etc) [yes C sucks]

@asb
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asb commented Jan 25, 2012

Regarding USB: APM have been trying to get the driver upstream but as you suggest, it's not looking hopeful http://thread.gmane.org/gmane.linux.usb.general/53348

@Alan-Cox
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There is a whole pile of stuff going on here, although I'm not entirely sure where the APM driver stuff went as it seems it was never submitted for staging as requested. Various vendors and groups of people are involved in trying to produce a single decent, clean, multi-arch upstream OTG core for these IP blocks, because they are all using them. It might be a good thing to worry about later on in any merge if the ugly driver works for now.

Alan

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
expkey_parse() oopses when handling a 0 length export. This is easily
triggerable from usermode by writing 0 bytes into
'/proc/[proc id]/net/rpc/nfsd.fh/channel'.

Below is the log:

[ 1402.286893] BUG: unable to handle kernel paging request at ffff880077c49fff
[ 1402.287632] IP: [<ffffffff812b4b99>] expkey_parse+0x28/0x2e1
[ 1402.287632] PGD 2206063 PUD 1fdfd067 PMD 1ffbc067 PTE 8000000077c49160
[ 1402.287632] Oops: 0000 [raspberrypi#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 1402.287632] CPU 1
[ 1402.287632] Pid: 20198, comm: trinity Not tainted 3.2.0-rc2-sasha-00058-gc65cd37 raspberrypi#6
[ 1402.287632] RIP: 0010:[<ffffffff812b4b99>]  [<ffffffff812b4b99>] expkey_parse+0x28/0x2e1
[ 1402.287632] RSP: 0018:ffff880077f0fd68  EFLAGS: 00010292
[ 1402.287632] RAX: ffff880077c49fff RBX: 00000000ffffffea RCX: 0000000001043400
[ 1402.287632] RDX: 0000000000000000 RSI: ffff880077c4a000 RDI: ffffffff82283de0
[ 1402.287632] RBP: ffff880077f0fe18 R08: 0000000000000001 R09: ffff880000000000
[ 1402.287632] R10: 0000000000000000 R11: 0000000000000001 R12: ffff880077c4a000
[ 1402.287632] R13: ffffffff82283de0 R14: 0000000001043400 R15: ffffffff82283de0
[ 1402.287632] FS:  00007f25fec3f700(0000) GS:ffff88007d400000(0000) knlGS:0000000000000000
[ 1402.287632] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1402.287632] CR2: ffff880077c49fff CR3: 0000000077e1d000 CR4: 00000000000406e0
[ 1402.287632] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1402.287632] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 1402.287632] Process trinity (pid: 20198, threadinfo ffff880077f0e000, task ffff880077db17b0)
[ 1402.287632] Stack:
[ 1402.287632]  ffff880077db17b0 ffff880077c4a000 ffff880077f0fdb8 ffffffff810b411e
[ 1402.287632]  ffff880000000000 ffff880077db17b0 ffff880077c4a000 ffffffff82283de0
[ 1402.287632]  0000000001043400 ffffffff82283de0 ffff880077f0fde8 ffffffff81111f63
[ 1402.287632] Call Trace:
[ 1402.287632]  [<ffffffff810b411e>] ? lock_release+0x1af/0x1bc
[ 1402.287632]  [<ffffffff81111f63>] ? might_fault+0x97/0x9e
[ 1402.287632]  [<ffffffff81111f1a>] ? might_fault+0x4e/0x9e
[ 1402.287632]  [<ffffffff81a8bcf2>] cache_do_downcall+0x3e/0x4f
[ 1402.287632]  [<ffffffff81a8c950>] cache_write.clone.16+0xbb/0x130
[ 1402.287632]  [<ffffffff81a8c9df>] ? cache_write_pipefs+0x1a/0x1a
[ 1402.287632]  [<ffffffff81a8c9f8>] cache_write_procfs+0x19/0x1b
[ 1402.287632]  [<ffffffff8118dc54>] proc_reg_write+0x8e/0xad
[ 1402.287632]  [<ffffffff8113fe81>] vfs_write+0xaa/0xfd
[ 1402.287632]  [<ffffffff8114142d>] ? fget_light+0x35/0x9e
[ 1402.287632]  [<ffffffff8113ff8b>] sys_write+0x48/0x6f
[ 1402.287632]  [<ffffffff81bbdb92>] system_call_fastpath+0x16/0x1b
[ 1402.287632] Code: c0 c9 c3 55 48 63 d2 48 89 e5 48 8d 44 32 ff 41 57 41 56 41 55 41 54 53 bb ea ff ff ff 48 81 ec 88 00 00 00 48 89 b5 58 ff ff ff
[ 1402.287632]  38 0a 0f 85 89 02 00 00 c6 00 00 48 8b 3d 44 4a e5 01 48 85
[ 1402.287632] RIP  [<ffffffff812b4b99>] expkey_parse+0x28/0x2e1
[ 1402.287632]  RSP <ffff880077f0fd68>
[ 1402.287632] CR2: ffff880077c49fff
[ 1402.287632] ---[ end trace 368ef53ff773a5e3 ]---

Cc: "J. Bruce Fields" <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
…S block during isolation for migration

When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 raspberrypi#1 [d72d3b24] oops_end at c05c5322
 raspberrypi#2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 raspberrypi#3 [d72d3bec] bad_area at c0227fb6
 raspberrypi#4 [d72d3c00] do_page_fault at c05c72ec
 raspberrypi#5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 raspberrypi#6 [d72d3cb4] isolate_migratepages at c030b15a
 raspberrypi#7 [d72d3d14] zone_watermark_ok at c02d26cb
 raspberrypi#8 [d72d3d2c] compact_zone at c030b8d
 raspberrypi#9 [d72d3d68] compact_zone_order at c030bba1
raspberrypi#10 [d72d3db4] try_to_compact_pages at c030bc84
raspberrypi#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
raspberrypi#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
raspberrypi#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
raspberrypi#14 [d72d3eb8] alloc_pages_vma at c030a845
raspberrypi#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
raspberrypi#16 [d72d3f00] handle_mm_fault at c02f36c6
raspberrypi#17 [d72d3f30] do_page_fault at c05c70ed
raspberrypi#18 [d72d3fb] error_code (via page_fault) at c05c47a4
    EAX: b71ff00  EBX: 00000001  ECX: 00001600  EDX: 0000043
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <[email protected]>
Tested-by: Herbert van den Bergh <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012
If the netdev is already in NETREG_UNREGISTERING/_UNREGISTERED state, do not
update the real num tx queues. netdev_queue_update_kobjects() is already
called via remove_queue_kobjects() at NETREG_UNREGISTERING time. So, when
upper layer driver, e.g., FCoE protocol stack is monitoring the netdev
event of NETDEV_UNREGISTER and calls back to LLD ndo_fcoe_disable() to remove
extra queues allocated for FCoE, the associated txq sysfs kobjects are already
removed, and trying to update the real num queues would cause something like
below:

...
PID: 25138  TASK: ffff88021e64c440  CPU: 3   COMMAND: "kworker/3:3"
 #0 [ffff88021f007760] machine_kexec at ffffffff810226d9
 raspberrypi#1 [ffff88021f0077d0] crash_kexec at ffffffff81089d2d
 raspberrypi#2 [ffff88021f0078a0] oops_end at ffffffff813bca78
 raspberrypi#3 [ffff88021f0078d0] no_context at ffffffff81029e72
 raspberrypi#4 [ffff88021f007920] __bad_area_nosemaphore at ffffffff8102a155
 raspberrypi#5 [ffff88021f0079f0] bad_area_nosemaphore at ffffffff8102a23e
 raspberrypi#6 [ffff88021f007a00] do_page_fault at ffffffff813bf32e
 raspberrypi#7 [ffff88021f007b10] page_fault at ffffffff813bc045
    [exception RIP: sysfs_find_dirent+17]
    RIP: ffffffff81178611  RSP: ffff88021f007bc0  RFLAGS: 00010246
    RAX: ffff88021e64c440  RBX: ffffffff8156cc63  RCX: 0000000000000004
    RDX: ffffffff8156cc63  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88021f007be0   R8: 0000000000000004   R9: 0000000000000008
    R10: ffffffff816fed00  R11: 0000000000000004  R12: 0000000000000000
    R13: ffffffff8156cc63  R14: 0000000000000000  R15: ffff8802222a0000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 raspberrypi#8 [ffff88021f007be8] sysfs_get_dirent at ffffffff81178c07
 raspberrypi#9 [ffff88021f007c18] sysfs_remove_group at ffffffff8117ac27
raspberrypi#10 [ffff88021f007c48] netdev_queue_update_kobjects at ffffffff813178f9
raspberrypi#11 [ffff88021f007c88] netif_set_real_num_tx_queues at ffffffff81303e38
raspberrypi#12 [ffff88021f007cc8] ixgbe_set_num_queues at ffffffffa0249763 [ixgbe]
raspberrypi#13 [ffff88021f007cf8] ixgbe_init_interrupt_scheme at ffffffffa024ea89 [ixgbe]
raspberrypi#14 [ffff88021f007d48] ixgbe_fcoe_disable at ffffffffa0267113 [ixgbe]
raspberrypi#15 [ffff88021f007d68] vlan_dev_fcoe_disable at ffffffffa014fef5 [8021q]
raspberrypi#16 [ffff88021f007d78] fcoe_interface_cleanup at ffffffffa02b7dfd [fcoe]
raspberrypi#17 [ffff88021f007df8] fcoe_destroy_work at ffffffffa02b7f08 [fcoe]
raspberrypi#18 [ffff88021f007e18] process_one_work at ffffffff8105d7ca
raspberrypi#19 [ffff88021f007e68] worker_thread at ffffffff81060513
raspberrypi#20 [ffff88021f007ee8] kthread at ffffffff810648b6
raspberrypi#21 [ffff88021f007f48] kernel_thread_helper at ffffffff813c40f4

Signed-off-by: Yi Zou <[email protected]>
Tested-by: Ross Brattain <[email protected]>
Tested-by: Stephen Ko <[email protected]>
Signed-off-by: Jeff Kirsher <[email protected]>
@sjenning
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I was looking at the dwc3 driver (drivers/usb/dwc3), and I think that the USB driver for the RPi's use can be drastically simplified. Afaik, the RPi just uses the Synopsis Designware USB2.0 OTG in host mode only. If that is the case you can just make a ECHI HCD wrapper for it, yes?

@sjenning
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Also, Alan, do you know if new ARM stuff is going to need to use Device Tree?

@Alan-Cox
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Device tree is a yes

The Designware USB is an ongoing mess (there are several variant drivers for it already most differing on the power handling side and they range from ARM to X86 devices). It's now at the point people are actively thinking about getting the mess sorted by turning it into one properly written driver but that will take a bit of time.

Certainly a wrapper might be a good initial integration approach until that is done.

@nomis
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nomis commented May 8, 2012

I'm working on reorganising the code into a device tree implementation for the base devices as I now have it booting a serial console only rebased against 3.4.

bootc pushed a commit to bootc/linux-rpi-orig that referenced this issue May 8, 2012
commit b2ea70a upstream.

expkey_parse() oopses when handling a 0 length export. This is easily
triggerable from usermode by writing 0 bytes into
'/proc/[proc id]/net/rpc/nfsd.fh/channel'.

Below is the log:

[ 1402.286893] BUG: unable to handle kernel paging request at ffff880077c49fff
[ 1402.287632] IP: [<ffffffff812b4b99>] expkey_parse+0x28/0x2e1
[ 1402.287632] PGD 2206063 PUD 1fdfd067 PMD 1ffbc067 PTE 8000000077c49160
[ 1402.287632] Oops: 0000 [raspberrypi#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 1402.287632] CPU 1
[ 1402.287632] Pid: 20198, comm: trinity Not tainted 3.2.0-rc2-sasha-00058-gc65cd37 raspberrypi#6
[ 1402.287632] RIP: 0010:[<ffffffff812b4b99>]  [<ffffffff812b4b99>] expkey_parse+0x28/0x2e1
[ 1402.287632] RSP: 0018:ffff880077f0fd68  EFLAGS: 00010292
[ 1402.287632] RAX: ffff880077c49fff RBX: 00000000ffffffea RCX: 0000000001043400
[ 1402.287632] RDX: 0000000000000000 RSI: ffff880077c4a000 RDI: ffffffff82283de0
[ 1402.287632] RBP: ffff880077f0fe18 R08: 0000000000000001 R09: ffff880000000000
[ 1402.287632] R10: 0000000000000000 R11: 0000000000000001 R12: ffff880077c4a000
[ 1402.287632] R13: ffffffff82283de0 R14: 0000000001043400 R15: ffffffff82283de0
[ 1402.287632] FS:  00007f25fec3f700(0000) GS:ffff88007d400000(0000) knlGS:0000000000000000
[ 1402.287632] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1402.287632] CR2: ffff880077c49fff CR3: 0000000077e1d000 CR4: 00000000000406e0
[ 1402.287632] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1402.287632] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 1402.287632] Process trinity (pid: 20198, threadinfo ffff880077f0e000, task ffff880077db17b0)
[ 1402.287632] Stack:
[ 1402.287632]  ffff880077db17b0 ffff880077c4a000 ffff880077f0fdb8 ffffffff810b411e
[ 1402.287632]  ffff880000000000 ffff880077db17b0 ffff880077c4a000 ffffffff82283de0
[ 1402.287632]  0000000001043400 ffffffff82283de0 ffff880077f0fde8 ffffffff81111f63
[ 1402.287632] Call Trace:
[ 1402.287632]  [<ffffffff810b411e>] ? lock_release+0x1af/0x1bc
[ 1402.287632]  [<ffffffff81111f63>] ? might_fault+0x97/0x9e
[ 1402.287632]  [<ffffffff81111f1a>] ? might_fault+0x4e/0x9e
[ 1402.287632]  [<ffffffff81a8bcf2>] cache_do_downcall+0x3e/0x4f
[ 1402.287632]  [<ffffffff81a8c950>] cache_write.clone.16+0xbb/0x130
[ 1402.287632]  [<ffffffff81a8c9df>] ? cache_write_pipefs+0x1a/0x1a
[ 1402.287632]  [<ffffffff81a8c9f8>] cache_write_procfs+0x19/0x1b
[ 1402.287632]  [<ffffffff8118dc54>] proc_reg_write+0x8e/0xad
[ 1402.287632]  [<ffffffff8113fe81>] vfs_write+0xaa/0xfd
[ 1402.287632]  [<ffffffff8114142d>] ? fget_light+0x35/0x9e
[ 1402.287632]  [<ffffffff8113ff8b>] sys_write+0x48/0x6f
[ 1402.287632]  [<ffffffff81bbdb92>] system_call_fastpath+0x16/0x1b
[ 1402.287632] Code: c0 c9 c3 55 48 63 d2 48 89 e5 48 8d 44 32 ff 41 57 41 56 41 55 41 54 53 bb ea ff ff ff 48 81 ec 88 00 00 00 48 89 b5 58 ff ff ff
[ 1402.287632]  38 0a 0f 85 89 02 00 00 c6 00 00 48 8b 3d 44 4a e5 01 48 85
[ 1402.287632] RIP  [<ffffffff812b4b99>] expkey_parse+0x28/0x2e1
[ 1402.287632]  RSP <ffff880077f0fd68>
[ 1402.287632] CR2: ffff880077c49fff
[ 1402.287632] ---[ end trace 368ef53ff773a5e3 ]---

Cc: "J. Bruce Fields" <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: [email protected]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
bootc pushed a commit to bootc/linux-rpi-orig that referenced this issue May 8, 2012
…S block during isolation for migration

commit 0bf380b upstream.

When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 raspberrypi#1 [d72d3b24] oops_end at c05c5322
 raspberrypi#2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 raspberrypi#3 [d72d3bec] bad_area at c0227fb6
 raspberrypi#4 [d72d3c00] do_page_fault at c05c72ec
 raspberrypi#5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 raspberrypi#6 [d72d3cb4] isolate_migratepages at c030b15a
 raspberrypi#7 [d72d3d14] zone_watermark_ok at c02d26cb
 raspberrypi#8 [d72d3d2c] compact_zone at c030b8d
 raspberrypi#9 [d72d3d68] compact_zone_order at c030bba1
raspberrypi#10 [d72d3db4] try_to_compact_pages at c030bc84
raspberrypi#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
raspberrypi#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
raspberrypi#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
raspberrypi#14 [d72d3eb8] alloc_pages_vma at c030a845
raspberrypi#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
raspberrypi#16 [d72d3f00] handle_mm_fault at c02f36c6
raspberrypi#17 [d72d3f30] do_page_fault at c05c70ed
raspberrypi#18 [d72d3fb] error_code (via page_fault) at c05c47a4
    EAX: b71ff00  EBX: 00000001  ECX: 00001600  EDX: 0000043
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <[email protected]>
Tested-by: Herbert van den Bergh <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Michal Nazarewicz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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nomis commented May 20, 2012

The usb driver is writing to freed memory: http://s85.org/aygDp9tm:view

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012
…condition

commit 26c1917 upstream.

When holding the mmap_sem for reading, pmd_offset_map_lock should only
run on a pmd_t that has been read atomically from the pmdp pointer,
otherwise we may read only half of it leading to this crash.

PID: 11679  TASK: f06e8000  CPU: 3   COMMAND: "do_race_2_panic"
 #0 [f06a9dd8] crash_kexec at c049b5ec
 raspberrypi#1 [f06a9e2c] oops_end at c083d1c2
 raspberrypi#2 [f06a9e40] no_context at c0433ded
 raspberrypi#3 [f06a9e64] bad_area_nosemaphore at c043401a
 raspberrypi#4 [f06a9e6c] __do_page_fault at c0434493
 raspberrypi#5 [f06a9eec] do_page_fault at c083eb45
 raspberrypi#6 [f06a9f04] error_code (via page_fault) at c083c5d5
    EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP:
    00000000
    DS:  007b     ESI: 9e201000 ES:  007b     EDI: 01fb4700 GS:  00e0
    CS:  0060     EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246
 raspberrypi#7 [f06a9f38] _spin_lock at c083bc14
 raspberrypi#8 [f06a9f44] sys_mincore at c0507b7d
 raspberrypi#9 [f06a9fb0] system_call at c083becd
                         start           len
    EAX: ffffffda  EBX: 9e200000  ECX: 00001000  EDX: 6228537f
    DS:  007b      ESI: 00000000  ES:  007b      EDI: 003d0f00
    SS:  007b      ESP: 62285354  EBP: 62285388  GS:  0033
    CS:  0073      EIP: 00291416  ERR: 000000da  EFLAGS: 00000286

This should be a longstanding bug affecting x86 32bit PAE without THP.
Only archs with 64bit large pmd_t and 32bit unsigned long should be
affected.

With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad()
would partly hide the bug when the pmd transition from none to stable,
by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is
enabled a new set of problem arises by the fact could then transition
freely in any of the none, pmd_trans_huge or pmd_trans_stable states.
So making the barrier in pmd_none_or_trans_huge_or_clear_bad()
unconditional isn't good idea and it would be a flakey solution.

This should be fully fixed by introducing a pmd_read_atomic that reads
the pmd in order with THP disabled, or by reading the pmd atomically
with cmpxchg8b with THP enabled.

Luckily this new race condition only triggers in the places that must
already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix
is localized there but this bug is not related to THP.

NOTE: this can trigger on x86 32bit systems with PAE enabled with more
than 4G of ram, otherwise the high part of the pmd will never risk to be
truncated because it would be zero at all times, in turn so hiding the
SMP race.

This bug was discovered and fully debugged by Ulrich, quote:

----
[..]
pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and
eax.

    496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t
    *pmd)
    497 {
    498         /* depend on compiler for an atomic pmd read */
    499         pmd_t pmdval = *pmd;

                                // edi = pmd pointer
0xc0507a74 <sys_mincore+548>:   mov    0x8(%esp),%edi
...
                                // edx = PTE page table high address
0xc0507a84 <sys_mincore+564>:   mov    0x4(%edi),%edx
...
                                // eax = PTE page table low address
0xc0507a8e <sys_mincore+574>:   mov    (%edi),%eax

[..]

Please note that the PMD is not read atomically. These are two "mov"
instructions where the high order bits of the PMD entry are fetched
first. Hence, the above machine code is prone to the following race.

-  The PMD entry {high|low} is 0x0000000000000000.
   The "mov" at 0xc0507a84 loads 0x00000000 into edx.

-  A page fault (on another CPU) sneaks in between the two "mov"
   instructions and instantiates the PMD.

-  The PMD entry {high|low} is now 0x00000003fda38067.
   The "mov" at 0xc0507a8e loads 0xfda38067 into eax.
----

Reported-by: Ulrich Obergfell <[email protected]>
Signed-off-by: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Larry Woodman <[email protected]>
Cc: Petr Matousek <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit to popcornmix/linux that referenced this issue Aug 16, 2012
commit 3cf003c upstream.

Jian found that when he ran fsx on a 32 bit arch with a large wsize the
process and one of the bdi writeback kthreads would sometimes deadlock
with a stack trace like this:

crash> bt
PID: 2789   TASK: f02edaa0  CPU: 3   COMMAND: "fsx"
 #0 [eed63cbc] schedule at c083c5b3
 raspberrypi#1 [eed63d80] kmap_high at c0500ec8
 raspberrypi#2 [eed63db0] cifs_async_writev at f7fabcd7 [cifs]
 raspberrypi#3 [eed63df0] cifs_writepages at f7fb7f5c [cifs]
 raspberrypi#4 [eed63e50] do_writepages at c04f3e32
 raspberrypi#5 [eed63e54] __filemap_fdatawrite_range at c04e152a
 raspberrypi#6 [eed63ea4] filemap_fdatawrite at c04e1b3e
 raspberrypi#7 [eed63eb4] cifs_file_aio_write at f7fa111a [cifs]
 raspberrypi#8 [eed63ecc] do_sync_write at c052d202
 raspberrypi#9 [eed63f74] vfs_write at c052d4ee
raspberrypi#10 [eed63f94] sys_write at c052df4c
raspberrypi#11 [eed63fb0] ia32_sysenter_target at c0409a98
    EAX: 00000004  EBX: 00000003  ECX: abd73b73  EDX: 012a65c6
    DS:  007b      ESI: 012a65c6  ES:  007b      EDI: 00000000
    SS:  007b      ESP: bf8db178  EBP: bf8db1f8  GS:  0033
    CS:  0073      EIP: 40000424  ERR: 00000004  EFLAGS: 00000246

Each task would kmap part of its address array before getting stuck, but
not enough to actually issue the write.

This patch fixes this by serializing the marshal_iov operations for
async reads and writes. The idea here is to ensure that cifs
aggressively tries to populate a request before attempting to fulfill
another one. As soon as all of the pages are kmapped for a request, then
we can unlock and allow another one to proceed.

There's no need to do this serialization on non-CONFIG_HIGHMEM arches
however, so optimize all of this out when CONFIG_HIGHMEM isn't set.

Reported-by: Jian Li <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <[email protected]>
popcornmix pushed a commit to popcornmix/linux that referenced this issue Aug 16, 2012
…d reasons

commit 5cf02d0 upstream.

We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

    PID: 2507   TASK: ffff88103691ab40  CPU: 14  COMMAND: "rpciod/14"
     #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
     raspberrypi#1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
     raspberrypi#2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
     raspberrypi#3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
     raspberrypi#4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
     raspberrypi#5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
     raspberrypi#6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
     raspberrypi#7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
     raspberrypi#8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
     raspberrypi#9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
    raspberrypi#10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
    raspberrypi#11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
    raspberrypi#12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
    raspberrypi#13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
    raspberrypi#14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
    raspberrypi#15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
    raspberrypi#16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
    raspberrypi#17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
    raspberrypi#18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
    raspberrypi#19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
    raspberrypi#20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
    raspberrypi#21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
    raspberrypi#22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
    raspberrypi#23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
    raspberrypi#24 [ffff8810343bfee8] kthread at ffffffff8108dd96
    raspberrypi#25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Ben Hutchings <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Printing the "start_ip" for every secondary cpu is very noisy on a large
system - and doesn't add any value. Drop this message.

Console log before:
Booting Node   0, Processors  #1
smpboot cpu 1: start_ip = 96000
 #2
smpboot cpu 2: start_ip = 96000
 #3
smpboot cpu 3: start_ip = 96000
 #4
smpboot cpu 4: start_ip = 96000
       ...
 #31
smpboot cpu 31: start_ip = 96000
Brought up 32 CPUs

Console log after:
Booting Node   0, Processors  #1 #2 #3 #4 #5 #6 #7 Ok.
Booting Node   1, Processors  #8 #9 #10 #11 #12 #13 #14 #15 Ok.
Booting Node   0, Processors  #16 #17 #18 #19 #20 #21 #22 #23 Ok.
Booting Node   1, Processors  #24 #25 #26 #27 #28 #29 #30 #31
Brought up 32 CPUs

Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Tony Luck <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
xfs_sync_worker checks the MS_ACTIVE flag in s_flags to avoid doing
work during mount and unmount.  This flag can be cleared by unmount
after the xfs_sync_worker checks it but before the work is completed.
The has caused crashes in the completion handler for the dummy
transaction commited by xfs_sync_worker:

PID: 27544  TASK: ffff88013544e040  CPU: 3   COMMAND: "kworker/3:0"
 #0 [ffff88016fdff930] machine_kexec at ffffffff810244e9
 #1 [ffff88016fdff9a0] crash_kexec at ffffffff8108d053
 #2 [ffff88016fdffa70] oops_end at ffffffff813ad1b8
 #3 [ffff88016fdffaa0] no_context at ffffffff8102bd48
 #4 [ffff88016fdffaf0] __bad_area_nosemaphore at ffffffff8102c04d
 #5 [ffff88016fdffb40] bad_area_nosemaphore at ffffffff8102c12e
 #6 [ffff88016fdffb50] do_page_fault at ffffffff813afaee
 #7 [ffff88016fdffc60] page_fault at ffffffff813ac635
    [exception RIP: xlog_get_lowest_lsn+0x30]
    RIP: ffffffffa04a9910  RSP: ffff88016fdffd10  RFLAGS: 00010246
    RAX: ffffc90014e48000  RBX: ffff88014d879980  RCX: ffff88014d879980
    RDX: ffff8802214ee4c0  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88016fdffd10   R8: ffff88014d879a80   R9: 0000000000000000
    R10: 0000000000000001  R11: 0000000000000000  R12: ffff8802214ee400
    R13: ffff88014d879980  R14: 0000000000000000  R15: ffff88022fd96605
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #8 [ffff88016fdffd18] xlog_state_do_callback at ffffffffa04aa186 [xfs]
 #9 [ffff88016fdffd98] xlog_state_done_syncing at ffffffffa04aa568 [xfs]

Protect xfs_sync_worker by using the s_umount semaphore at the read
level to provide exclusion with unmount while work is progressing.

Reviewed-by: Mark Tinguely <[email protected]>
Signed-off-by: Ben Myers <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
…condition

When holding the mmap_sem for reading, pmd_offset_map_lock should only
run on a pmd_t that has been read atomically from the pmdp pointer,
otherwise we may read only half of it leading to this crash.

PID: 11679  TASK: f06e8000  CPU: 3   COMMAND: "do_race_2_panic"
 #0 [f06a9dd8] crash_kexec at c049b5ec
 #1 [f06a9e2c] oops_end at c083d1c2
 #2 [f06a9e40] no_context at c0433ded
 #3 [f06a9e64] bad_area_nosemaphore at c043401a
 #4 [f06a9e6c] __do_page_fault at c0434493
 #5 [f06a9eec] do_page_fault at c083eb45
 #6 [f06a9f04] error_code (via page_fault) at c083c5d5
    EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP:
    00000000
    DS:  007b     ESI: 9e201000 ES:  007b     EDI: 01fb4700 GS:  00e0
    CS:  0060     EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246
 #7 [f06a9f38] _spin_lock at c083bc14
 #8 [f06a9f44] sys_mincore at c0507b7d
 #9 [f06a9fb0] system_call at c083becd
                         start           len
    EAX: ffffffda  EBX: 9e200000  ECX: 00001000  EDX: 6228537f
    DS:  007b      ESI: 00000000  ES:  007b      EDI: 003d0f00
    SS:  007b      ESP: 62285354  EBP: 62285388  GS:  0033
    CS:  0073      EIP: 00291416  ERR: 000000da  EFLAGS: 00000286

This should be a longstanding bug affecting x86 32bit PAE without THP.
Only archs with 64bit large pmd_t and 32bit unsigned long should be
affected.

With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad()
would partly hide the bug when the pmd transition from none to stable,
by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is
enabled a new set of problem arises by the fact could then transition
freely in any of the none, pmd_trans_huge or pmd_trans_stable states.
So making the barrier in pmd_none_or_trans_huge_or_clear_bad()
unconditional isn't good idea and it would be a flakey solution.

This should be fully fixed by introducing a pmd_read_atomic that reads
the pmd in order with THP disabled, or by reading the pmd atomically
with cmpxchg8b with THP enabled.

Luckily this new race condition only triggers in the places that must
already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix
is localized there but this bug is not related to THP.

NOTE: this can trigger on x86 32bit systems with PAE enabled with more
than 4G of ram, otherwise the high part of the pmd will never risk to be
truncated because it would be zero at all times, in turn so hiding the
SMP race.

This bug was discovered and fully debugged by Ulrich, quote:

----
[..]
pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and
eax.

    496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t
    *pmd)
    497 {
    498         /* depend on compiler for an atomic pmd read */
    499         pmd_t pmdval = *pmd;

                                // edi = pmd pointer
0xc0507a74 <sys_mincore+548>:   mov    0x8(%esp),%edi
...
                                // edx = PTE page table high address
0xc0507a84 <sys_mincore+564>:   mov    0x4(%edi),%edx
...
                                // eax = PTE page table low address
0xc0507a8e <sys_mincore+574>:   mov    (%edi),%eax

[..]

Please note that the PMD is not read atomically. These are two "mov"
instructions where the high order bits of the PMD entry are fetched
first. Hence, the above machine code is prone to the following race.

-  The PMD entry {high|low} is 0x0000000000000000.
   The "mov" at 0xc0507a84 loads 0x00000000 into edx.

-  A page fault (on another CPU) sneaks in between the two "mov"
   instructions and instantiates the PMD.

-  The PMD entry {high|low} is now 0x00000003fda38067.
   The "mov" at 0xc0507a8e loads 0xfda38067 into eax.
----

Reported-by: Ulrich Obergfell <[email protected]>
Signed-off-by: Andrea Arcangeli <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Larry Woodman <[email protected]>
Cc: Petr Matousek <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
… by ipw2100_pci_init_one

The problem was found by Larry Finger:
http://marc.info/?l=linux-wireless&m=133702401700614&w=2

The problem is identical to the one for ipw2200 which is already fixed:
http://marc.info/?l=linux-wireless&m=133457257407196&w=2

[   17.766431] ------------[ cut here ]------------
[   17.766467] WARNING: at net/wireless/core.c:562 wiphy_register+0x34c/0x3c0 [cfg80211]()
[   17.766471] Hardware name: Latitude D600
[   17.766474] Modules linked in: ipw2100(+) libipw pcmcia cfg80211 ppdev parport_pc yenta_socket sr_mod pcmcia_rsrc parport iTCO_wdt cdrom sg rfkill pcmcia_
core lib80211 tg3 video button battery ac iTCO_vendor_support joydev shpchp pcspkr pciehp pci_hotplug autofs4 radeon ttm drm_kms_helper uhci_hcd ehci_hcd rtc
_cmos thermal drm hwmon i2c_algo_bit i2c_core processor usbcore usb_common ata_generic ata_piix ahci libahci libata
[   17.766525] Pid: 474, comm: modprobe Not tainted 3.4.0-rc7-wl+ #6
[   17.766528] Call Trace:
[   17.766541]  [<c066ad08>] ? printk+0x28/0x2a
[   17.766552]  [<c0230edd>] warn_slowpath_common+0x6d/0xa0
[   17.766563]  [<e0b253bc>] ? wiphy_register+0x34c/0x3c0 [cfg80211]
[   17.766573]  [<e0b253bc>] ? wiphy_register+0x34c/0x3c0 [cfg80211]
[   17.766578]  [<c0230f2d>] warn_slowpath_null+0x1d/0x20
[   17.766588]  [<e0b253bc>] wiphy_register+0x34c/0x3c0 [cfg80211]
[   17.766605]  [<e0b5b0d6>] ipw2100_wdev_init+0x196/0x1c0 [ipw2100]
[   17.766616]  [<e0b5d962>] ipw2100_pci_init_one+0x2b2/0x694 [ipw2100]
[   17.766632]  [<c047ce52>] local_pci_probe+0x42/0xb0
[   17.766637]  [<c047e2b0>] pci_device_probe+0x60/0x90
[   17.766645]  [<c0376de2>] ? sysfs_create_link+0x12/0x20
[   17.766654]  [<c050f1f6>] really_probe+0x56/0x2e0
[   17.766659]  [<c037636d>] ? create_dir+0x5d/0xa0
[   17.766667]  [<c0518c6b>] ? pm_runtime_barrier+0x3b/0xa0
[   17.766672]  [<c050f5e4>] driver_probe_device+0x44/0xa0
[   17.766677]  [<c047e227>] ? pci_match_device+0x97/0xa0
[   17.766681]  [<c050f6c9>] __driver_attach+0x89/0x90
[   17.766686]  [<c050f640>] ? driver_probe_device+0xa0/0xa0
[   17.766691]  [<c050da2a>] bus_for_each_dev+0x3a/0x70
[   17.766695]  [<c050ee6c>] driver_attach+0x1c/0x30
[   17.766699]  [<c050f640>] ? driver_probe_device+0xa0/0xa0
[   17.766704]  [<c050ea77>] bus_add_driver+0x187/0x280
[   17.766710]  [<c045b9cd>] ? kset_find_obj+0x2d/0x60
[   17.766715]  [<c047e2e0>] ? pci_device_probe+0x90/0x90
[   17.766719]  [<c047e2e0>] ? pci_device_probe+0x90/0x90
[   17.766724]  [<c050fb85>] driver_register+0x65/0x110
[   17.766729]  [<c047e09d>] __pci_register_driver+0x3d/0xa0
[   17.766738]  [<e09f705c>] ipw2100_init+0x5c/0x1000 [ipw2100]
[   17.766743]  [<c020110f>] do_one_initcall+0x2f/0x170
[   17.766749]  [<e09f7000>] ? 0xe09f6fff
[   17.766757]  [<c0287ce8>] sys_init_module+0xa8/0x210
[   17.766766]  [<c067a075>] syscall_call+0x7/0xb
[   17.766769] ---[ end trace 559898c6bb0d1c75 ]---
[   17.767093] ipw2100: probe of 0000:02:03.0 failed with error -5

This warning appears only if we apply Ben Hutchings' fix
http://marc.info/?l=linux-wireless&m=132720204412667&w=2
for the bug reported by Cesare Leonardi
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=656813
with cfg80211 warning during device registration
("cfg80211: failed to add phy80211 symlink to netdev!").

We separate device bring up and registration with network stack
to avoid the problem.

Signed-off-by: Stanislav Yakovlev <[email protected]>
Tested-by: Larry Finger <[email protected]>
Signed-off-by: John W. Linville <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
The warning below triggers on AMD MCM packages because physical package
IDs on the cores of a _physical_ socket are the same. I.e., this field
says which CPUs belong to the same physical package.

However, the same two CPUs belong to two different internal, i.e.
"logical" nodes in the same physical socket which is reflected in the
CPU-to-node map on x86 with NUMA.

Which makes this check wrong on the above topologies so circumvent it.

[    0.444413] Booting Node   0, Processors  #1 #2 #3 #4 #5 Ok.
[    0.461388] ------------[ cut here ]------------
[    0.465997] WARNING: at arch/x86/kernel/smpboot.c:310 topology_sane.clone.1+0x6e/0x81()
[    0.473960] Hardware name: Dinar
[    0.477170] sched: CPU #6's mc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency.
[    0.486860] Booting Node   1, Processors  #6
[    0.491104] Modules linked in:
[    0.494141] Pid: 0, comm: swapper/6 Not tainted 3.4.0+ #1
[    0.499510] Call Trace:
[    0.501946]  [<ffffffff8144bf92>] ? topology_sane.clone.1+0x6e/0x81
[    0.508185]  [<ffffffff8102f1fc>] warn_slowpath_common+0x85/0x9d
[    0.514163]  [<ffffffff8102f2b7>] warn_slowpath_fmt+0x46/0x48
[    0.519881]  [<ffffffff8144bf92>] topology_sane.clone.1+0x6e/0x81
[    0.525943]  [<ffffffff8144c234>] set_cpu_sibling_map+0x251/0x371
[    0.532004]  [<ffffffff8144c4ee>] start_secondary+0x19a/0x218
[    0.537729] ---[ end trace 4eaa2a86a8e2da22 ]---
[    0.628197]  #7 #8 #9 #10 #11 Ok.
[    0.807108] Booting Node   3, Processors  #12 #13 #14 #15 #16 #17 Ok.
[    0.897587] Booting Node   2, Processors  #18 #19 #20 #21 #22 #23 Ok.
[    0.917443] Brought up 24 CPUs

We ran a topology sanity check test we have here on it and
it all looks ok... hopefully :).

Signed-off-by: Borislav Petkov <[email protected]>
Cc: Andreas Herrmann <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Jian found that when he ran fsx on a 32 bit arch with a large wsize the
process and one of the bdi writeback kthreads would sometimes deadlock
with a stack trace like this:

crash> bt
PID: 2789   TASK: f02edaa0  CPU: 3   COMMAND: "fsx"
 #0 [eed63cbc] schedule at c083c5b3
 #1 [eed63d80] kmap_high at c0500ec8
 #2 [eed63db0] cifs_async_writev at f7fabcd7 [cifs]
 #3 [eed63df0] cifs_writepages at f7fb7f5c [cifs]
 #4 [eed63e50] do_writepages at c04f3e32
 #5 [eed63e54] __filemap_fdatawrite_range at c04e152a
 #6 [eed63ea4] filemap_fdatawrite at c04e1b3e
 #7 [eed63eb4] cifs_file_aio_write at f7fa111a [cifs]
 #8 [eed63ecc] do_sync_write at c052d202
 #9 [eed63f74] vfs_write at c052d4ee
#10 [eed63f94] sys_write at c052df4c
#11 [eed63fb0] ia32_sysenter_target at c0409a98
    EAX: 00000004  EBX: 00000003  ECX: abd73b73  EDX: 012a65c6
    DS:  007b      ESI: 012a65c6  ES:  007b      EDI: 00000000
    SS:  007b      ESP: bf8db178  EBP: bf8db1f8  GS:  0033
    CS:  0073      EIP: 40000424  ERR: 00000004  EFLAGS: 00000246

Each task would kmap part of its address array before getting stuck, but
not enough to actually issue the write.

This patch fixes this by serializing the marshal_iov operations for
async reads and writes. The idea here is to ensure that cifs
aggressively tries to populate a request before attempting to fulfill
another one. As soon as all of the pages are kmapped for a request, then
we can unlock and allow another one to proceed.

There's no need to do this serialization on non-CONFIG_HIGHMEM arches
however, so optimize all of this out when CONFIG_HIGHMEM isn't set.

Cc: <[email protected]>
Reported-by: Jian Li <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
…d reasons

We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

    PID: 2507   TASK: ffff88103691ab40  CPU: 14  COMMAND: "rpciod/14"
     #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
     #1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
     #2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
     #3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
     #4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
     #5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
     #6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
     #7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
     #8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
     #9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
    #10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
    #11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
    #12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
    #13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
    #14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
    #15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
    #16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
    #17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
    #18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
    #19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
    #20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
    #21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
    #22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
    #23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
    #24 [ffff8810343bfee8] kthread at ffffffff8108dd96
    #25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
Cc: [email protected]
popcornmix pushed a commit that referenced this issue Oct 13, 2012
On architectures where cputime_t is 64 bit type, is possible to trigger
divide by zero on do_div(temp, (__force u32) total) line, if total is a
non zero number but has lower 32 bit's zeroed. Removing casting is not
a good solution since some do_div() implementations do cast to u32
internally.

This problem can be triggered in practice on very long lived processes:

  PID: 2331   TASK: ffff880472814b00  CPU: 2   COMMAND: "oraagent.bin"
   #0 [ffff880472a51b70] machine_kexec at ffffffff8103214b
   #1 [ffff880472a51bd0] crash_kexec at ffffffff810b91c2
   #2 [ffff880472a51ca0] oops_end at ffffffff814f0b00
   #3 [ffff880472a51cd0] die at ffffffff8100f26b
   #4 [ffff880472a51d00] do_trap at ffffffff814f03f4
   #5 [ffff880472a51d60] do_divide_error at ffffffff8100cfff
   #6 [ffff880472a51e00] divide_error at ffffffff8100be7b
      [exception RIP: thread_group_times+0x56]
      RIP: ffffffff81056a16  RSP: ffff880472a51eb8  RFLAGS: 00010046
      RAX: bc3572c9fe12d194  RBX: ffff880874150800  RCX: 0000000110266fad
      RDX: 0000000000000000  RSI: ffff880472a51eb8  RDI: 001038ae7d9633dc
      RBP: ffff880472a51ef8   R8: 00000000b10a3a64   R9: ffff880874150800
      R10: 00007fcba27ab680  R11: 0000000000000202  R12: ffff880472a51f08
      R13: ffff880472a51f10  R14: 0000000000000000  R15: 0000000000000007
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
   #7 [ffff880472a51f00] do_sys_times at ffffffff8108845d
   #8 [ffff880472a51f40] sys_times at ffffffff81088524
   #9 [ffff880472a51f80] system_call_fastpath at ffffffff8100b0f2
      RIP: 0000003808caac3a  RSP: 00007fcba27ab6d8  RFLAGS: 00000202
      RAX: 0000000000000064  RBX: ffffffff8100b0f2  RCX: 0000000000000000
      RDX: 00007fcba27ab6e0  RSI: 000000000076d58e  RDI: 00007fcba27ab6e0
      RBP: 00007fcba27ab700   R8: 0000000000000020   R9: 000000000000091b
      R10: 00007fcba27ab680  R11: 0000000000000202  R12: 00007fff9ca41940
      R13: 0000000000000000  R14: 00007fcba27ac9c0  R15: 00007fff9ca41940
      ORIG_RAX: 0000000000000064  CS: 0033  SS: 002b

Cc: [email protected]
Signed-off-by: Stanislaw Gruszka <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
popcornmix pushed a commit that referenced this issue Oct 13, 2012
Fixes following lockdep splat :

[ 1614.734896] =============================================
[ 1614.734898] [ INFO: possible recursive locking detected ]
[ 1614.734901] 3.6.0-rc3+ #782 Not tainted
[ 1614.734903] ---------------------------------------------
[ 1614.734905] swapper/11/0 is trying to acquire lock:
[ 1614.734907]  (slock-AF_INET){+.-...}, at: [<ffffffffa0209d72>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.734920]
[ 1614.734920] but task is already holding lock:
[ 1614.734922]  (slock-AF_INET){+.-...}, at: [<ffffffff815fce23>] tcp_v4_err+0x163/0x6b0
[ 1614.734932]
[ 1614.734932] other info that might help us debug this:
[ 1614.734935]  Possible unsafe locking scenario:
[ 1614.734935]
[ 1614.734937]        CPU0
[ 1614.734938]        ----
[ 1614.734940]   lock(slock-AF_INET);
[ 1614.734943]   lock(slock-AF_INET);
[ 1614.734946]
[ 1614.734946]  *** DEADLOCK ***
[ 1614.734946]
[ 1614.734949]  May be due to missing lock nesting notation
[ 1614.734949]
[ 1614.734952] 7 locks held by swapper/11/0:
[ 1614.734954]  #0:  (rcu_read_lock){.+.+..}, at: [<ffffffff81592801>] __netif_receive_skb+0x251/0xd00
[ 1614.734964]  #1:  (rcu_read_lock){.+.+..}, at: [<ffffffff815d319c>] ip_local_deliver_finish+0x4c/0x4e0
[ 1614.734972]  #2:  (rcu_read_lock){.+.+..}, at: [<ffffffff8160d116>] icmp_socket_deliver+0x46/0x230
[ 1614.734982]  #3:  (slock-AF_INET){+.-...}, at: [<ffffffff815fce23>] tcp_v4_err+0x163/0x6b0
[ 1614.734989]  #4:  (rcu_read_lock){.+.+..}, at: [<ffffffff815da240>] ip_queue_xmit+0x0/0x680
[ 1614.734997]  #5:  (rcu_read_lock_bh){.+....}, at: [<ffffffff815d9925>] ip_finish_output+0x135/0x890
[ 1614.735004]  #6:  (rcu_read_lock_bh){.+....}, at: [<ffffffff81595680>] dev_queue_xmit+0x0/0xe00
[ 1614.735012]
[ 1614.735012] stack backtrace:
[ 1614.735016] Pid: 0, comm: swapper/11 Not tainted 3.6.0-rc3+ #782
[ 1614.735018] Call Trace:
[ 1614.735020]  <IRQ>  [<ffffffff810a50ac>] __lock_acquire+0x144c/0x1b10
[ 1614.735033]  [<ffffffff810a334b>] ? check_usage+0x9b/0x4d0
[ 1614.735037]  [<ffffffff810a6762>] ? mark_held_locks+0x82/0x130
[ 1614.735042]  [<ffffffff810a5df0>] lock_acquire+0x90/0x200
[ 1614.735047]  [<ffffffffa0209d72>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.735051]  [<ffffffff810a69ad>] ? trace_hardirqs_on+0xd/0x10
[ 1614.735060]  [<ffffffff81749b31>] _raw_spin_lock+0x41/0x50
[ 1614.735065]  [<ffffffffa0209d72>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.735069]  [<ffffffffa0209d72>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.735075]  [<ffffffffa014f7f2>] l2tp_eth_dev_xmit+0x32/0x60 [l2tp_eth]
[ 1614.735079]  [<ffffffff81595112>] dev_hard_start_xmit+0x502/0xa70
[ 1614.735083]  [<ffffffff81594c6e>] ? dev_hard_start_xmit+0x5e/0xa70
[ 1614.735087]  [<ffffffff815957c1>] ? dev_queue_xmit+0x141/0xe00
[ 1614.735093]  [<ffffffff815b622e>] sch_direct_xmit+0xfe/0x290
[ 1614.735098]  [<ffffffff81595865>] dev_queue_xmit+0x1e5/0xe00
[ 1614.735102]  [<ffffffff81595680>] ? dev_hard_start_xmit+0xa70/0xa70
[ 1614.735106]  [<ffffffff815b4daa>] ? eth_header+0x3a/0xf0
[ 1614.735111]  [<ffffffff8161d33e>] ? fib_get_table+0x2e/0x280
[ 1614.735117]  [<ffffffff8160a7e2>] arp_xmit+0x22/0x60
[ 1614.735121]  [<ffffffff8160a863>] arp_send+0x43/0x50
[ 1614.735125]  [<ffffffff8160b82f>] arp_solicit+0x18f/0x450
[ 1614.735132]  [<ffffffff8159d9da>] neigh_probe+0x4a/0x70
[ 1614.735137]  [<ffffffff815a191a>] __neigh_event_send+0xea/0x300
[ 1614.735141]  [<ffffffff815a1c93>] neigh_resolve_output+0x163/0x260
[ 1614.735146]  [<ffffffff815d9cf5>] ip_finish_output+0x505/0x890
[ 1614.735150]  [<ffffffff815d9925>] ? ip_finish_output+0x135/0x890
[ 1614.735154]  [<ffffffff815dae79>] ip_output+0x59/0xf0
[ 1614.735158]  [<ffffffff815da1cd>] ip_local_out+0x2d/0xa0
[ 1614.735162]  [<ffffffff815da403>] ip_queue_xmit+0x1c3/0x680
[ 1614.735165]  [<ffffffff815da240>] ? ip_local_out+0xa0/0xa0
[ 1614.735172]  [<ffffffff815f4402>] tcp_transmit_skb+0x402/0xa60
[ 1614.735177]  [<ffffffff815f5a11>] tcp_retransmit_skb+0x1a1/0x620
[ 1614.735181]  [<ffffffff815f7e93>] tcp_retransmit_timer+0x393/0x960
[ 1614.735185]  [<ffffffff815fce23>] ? tcp_v4_err+0x163/0x6b0
[ 1614.735189]  [<ffffffff815fd317>] tcp_v4_err+0x657/0x6b0
[ 1614.735194]  [<ffffffff8160d116>] ? icmp_socket_deliver+0x46/0x230
[ 1614.735199]  [<ffffffff8160d19e>] icmp_socket_deliver+0xce/0x230
[ 1614.735203]  [<ffffffff8160d116>] ? icmp_socket_deliver+0x46/0x230
[ 1614.735208]  [<ffffffff8160d464>] icmp_unreach+0xe4/0x2c0
[ 1614.735213]  [<ffffffff8160e520>] icmp_rcv+0x350/0x4a0
[ 1614.735217]  [<ffffffff815d3285>] ip_local_deliver_finish+0x135/0x4e0
[ 1614.735221]  [<ffffffff815d319c>] ? ip_local_deliver_finish+0x4c/0x4e0
[ 1614.735225]  [<ffffffff815d3ffa>] ip_local_deliver+0x4a/0x90
[ 1614.735229]  [<ffffffff815d37b7>] ip_rcv_finish+0x187/0x730
[ 1614.735233]  [<ffffffff815d425d>] ip_rcv+0x21d/0x300
[ 1614.735237]  [<ffffffff81592a1b>] __netif_receive_skb+0x46b/0xd00
[ 1614.735241]  [<ffffffff81592801>] ? __netif_receive_skb+0x251/0xd00
[ 1614.735245]  [<ffffffff81593368>] process_backlog+0xb8/0x180
[ 1614.735249]  [<ffffffff81593cf9>] net_rx_action+0x159/0x330
[ 1614.735257]  [<ffffffff810491f0>] __do_softirq+0xd0/0x3e0
[ 1614.735264]  [<ffffffff8109ed24>] ? tick_program_event+0x24/0x30
[ 1614.735270]  [<ffffffff8175419c>] call_softirq+0x1c/0x30
[ 1614.735278]  [<ffffffff8100425d>] do_softirq+0x8d/0xc0
[ 1614.735282]  [<ffffffff8104983e>] irq_exit+0xae/0xe0
[ 1614.735287]  [<ffffffff8175494e>] smp_apic_timer_interrupt+0x6e/0x99
[ 1614.735291]  [<ffffffff81753a1c>] apic_timer_interrupt+0x6c/0x80
[ 1614.735293]  <EOI>  [<ffffffff810a14ad>] ? trace_hardirqs_off+0xd/0x10
[ 1614.735306]  [<ffffffff81336f85>] ? intel_idle+0xf5/0x150
[ 1614.735310]  [<ffffffff81336f7e>] ? intel_idle+0xee/0x150
[ 1614.735317]  [<ffffffff814e6ea9>] cpuidle_enter+0x19/0x20
[ 1614.735321]  [<ffffffff814e7538>] cpuidle_idle_call+0xa8/0x630
[ 1614.735327]  [<ffffffff8100c1ba>] cpu_idle+0x8a/0xe0
[ 1614.735333]  [<ffffffff8173762e>] start_secondary+0x220/0x222

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
popcornmix pushed a commit that referenced this issue Dec 11, 2012
commit 412d32e upstream.

A rescue thread exiting TASK_INTERRUPTIBLE can lead to a task scheduling
off, never to be seen again.  In the case where this occurred, an exiting
thread hit reiserfs homebrew conditional resched while holding a mutex,
bringing the box to its knees.

PID: 18105  TASK: ffff8807fd412180  CPU: 5   COMMAND: "kdmflush"
 #0 [ffff8808157e7670] schedule at ffffffff8143f489
 #1 [ffff8808157e77b8] reiserfs_get_block at ffffffffa038ab2d [reiserfs]
 #2 [ffff8808157e79a8] __block_write_begin at ffffffff8117fb14
 #3 [ffff8808157e7a98] reiserfs_write_begin at ffffffffa0388695 [reiserfs]
 #4 [ffff8808157e7ad8] generic_perform_write at ffffffff810ee9e2
 #5 [ffff8808157e7b58] generic_file_buffered_write at ffffffff810eeb41
 #6 [ffff8808157e7ba8] __generic_file_aio_write at ffffffff810f1a3a
 #7 [ffff8808157e7c58] generic_file_aio_write at ffffffff810f1c88
 #8 [ffff8808157e7cc8] do_sync_write at ffffffff8114f850
 #9 [ffff8808157e7dd8] do_acct_process at ffffffff810a268f
    [exception RIP: kernel_thread_helper]
    RIP: ffffffff8144a5c0  RSP: ffff8808157e7f58  RFLAGS: 00000202
    RAX: 0000000000000000  RBX: 0000000000000000  RCX: 0000000000000000
    RDX: 0000000000000000  RSI: ffffffff8107af60  RDI: ffff8803ee491d18
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000000
    R10: 0000000000000000  R11: 0000000000000000  R12: 0000000000000000
    R13: 0000000000000000  R14: 0000000000000000  R15: 0000000000000000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Signed-off-by: Mike Galbraith <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Olipro pushed a commit to Olipro/linux-RPi that referenced this issue Dec 26, 2012
This moves ARM over to the asm-generic/unaligned.h header. This has the
benefit of better code generated especially for ARMv7 on gcc 4.7+
compilers.

As Arnd Bergmann, points out: The asm-generic version uses the "struct"
version for native-endian unaligned access and the "byteshift" version
for the opposite endianess. The current ARM version however uses the
"byteshift" implementation for both.

Thanks to Nicolas Pitre for the excellent analysis:

Test case:

int foo (int *x) { return get_unaligned(x); }
long long bar (long long *x) { return get_unaligned(x); }

With the current ARM version:

foo:
	ldrb	r3, [r0, raspberrypi#2]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 2B], MEM[(const u8 *)x_1(D) + 2B]
	ldrb	r1, [r0, raspberrypi#1]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 1B], MEM[(const u8 *)x_1(D) + 1B]
	ldrb	r2, [r0, #0]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D)], MEM[(const u8 *)x_1(D)]
	mov	r3, r3, asl raspberrypi#16	@ tmp154, MEM[(const u8 *)x_1(D) + 2B],
	ldrb	r0, [r0, raspberrypi#3]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 3B], MEM[(const u8 *)x_1(D) + 3B]
	orr	r3, r3, r1, asl raspberrypi#8	@, tmp155, tmp154, MEM[(const u8 *)x_1(D) + 1B],
	orr	r3, r3, r2	@ tmp157, tmp155, MEM[(const u8 *)x_1(D)]
	orr	r0, r3, r0, asl raspberrypi#24	@,, tmp157, MEM[(const u8 *)x_1(D) + 3B],
	bx	lr	@

bar:
	stmfd	sp!, {r4, r5, r6, r7}	@,
	mov	r2, #0	@ tmp184,
	ldrb	r5, [r0, raspberrypi#6]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 6B], MEM[(const u8 *)x_1(D) + 6B]
	ldrb	r4, [r0, raspberrypi#5]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 5B], MEM[(const u8 *)x_1(D) + 5B]
	ldrb	ip, [r0, raspberrypi#2]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 2B], MEM[(const u8 *)x_1(D) + 2B]
	ldrb	r1, [r0, raspberrypi#4]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 4B], MEM[(const u8 *)x_1(D) + 4B]
	mov	r5, r5, asl raspberrypi#16	@ tmp175, MEM[(const u8 *)x_1(D) + 6B],
	ldrb	r7, [r0, raspberrypi#1]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 1B], MEM[(const u8 *)x_1(D) + 1B]
	orr	r5, r5, r4, asl raspberrypi#8	@, tmp176, tmp175, MEM[(const u8 *)x_1(D) + 5B],
	ldrb	r6, [r0, raspberrypi#7]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 7B], MEM[(const u8 *)x_1(D) + 7B]
	orr	r5, r5, r1	@ tmp178, tmp176, MEM[(const u8 *)x_1(D) + 4B]
	ldrb	r4, [r0, #0]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D)], MEM[(const u8 *)x_1(D)]
	mov	ip, ip, asl raspberrypi#16	@ tmp188, MEM[(const u8 *)x_1(D) + 2B],
	ldrb	r1, [r0, raspberrypi#3]	@ zero_extendqisi2	@ MEM[(const u8 *)x_1(D) + 3B], MEM[(const u8 *)x_1(D) + 3B]
	orr	ip, ip, r7, asl raspberrypi#8	@, tmp189, tmp188, MEM[(const u8 *)x_1(D) + 1B],
	orr	r3, r5, r6, asl raspberrypi#24	@,, tmp178, MEM[(const u8 *)x_1(D) + 7B],
	orr	ip, ip, r4	@ tmp191, tmp189, MEM[(const u8 *)x_1(D)]
	orr	ip, ip, r1, asl raspberrypi#24	@, tmp194, tmp191, MEM[(const u8 *)x_1(D) + 3B],
	mov	r1, r3	@,
	orr	r0, r2, ip	@ tmp171, tmp184, tmp194
	ldmfd	sp!, {r4, r5, r6, r7}
	bx	lr

In both cases the code is slightly suboptimal.  One may wonder why
wasting r2 with the constant 0 in the second case for example.  And all
the mov's could be folded in subsequent orr's, etc.

Now with the asm-generic version:

foo:
	ldr	r0, [r0, #0]	@ unaligned	@,* x
	bx	lr	@

bar:
	mov	r3, r0	@ x, x
	ldr	r0, [r0, #0]	@ unaligned	@,* x
	ldr	r1, [r3, raspberrypi#4]	@ unaligned	@,
	bx	lr	@

This is way better of course, but only because this was compiled for
ARMv7. In this case the compiler knows that the hardware can do
unaligned word access.  This isn't that obvious for foo(), but if we
remove the get_unaligned() from bar as follows:

long long bar (long long *x) {return *x; }

then the resulting code is:

bar:
	ldmia	r0, {r0, r1}	@ x,,
	bx	lr	@

So this proves that the presumed aligned vs unaligned cases does have
influence on the instructions the compiler may use and that the above
unaligned code results are not just an accident.

Still... this isn't fully conclusive without at least looking at the
resulting assembly fron a pre ARMv6 compilation.  Let's see with an
ARMv5 target:

foo:
	ldrb	r3, [r0, #0]	@ zero_extendqisi2	@ tmp139,* x
	ldrb	r1, [r0, raspberrypi#1]	@ zero_extendqisi2	@ tmp140,
	ldrb	r2, [r0, raspberrypi#2]	@ zero_extendqisi2	@ tmp143,
	ldrb	r0, [r0, raspberrypi#3]	@ zero_extendqisi2	@ tmp146,
	orr	r3, r3, r1, asl raspberrypi#8	@, tmp142, tmp139, tmp140,
	orr	r3, r3, r2, asl raspberrypi#16	@, tmp145, tmp142, tmp143,
	orr	r0, r3, r0, asl raspberrypi#24	@,, tmp145, tmp146,
	bx	lr	@

bar:
	stmfd	sp!, {r4, r5, r6, r7}	@,
	ldrb	r2, [r0, #0]	@ zero_extendqisi2	@ tmp139,* x
	ldrb	r7, [r0, raspberrypi#1]	@ zero_extendqisi2	@ tmp140,
	ldrb	r3, [r0, raspberrypi#4]	@ zero_extendqisi2	@ tmp149,
	ldrb	r6, [r0, raspberrypi#5]	@ zero_extendqisi2	@ tmp150,
	ldrb	r5, [r0, raspberrypi#2]	@ zero_extendqisi2	@ tmp143,
	ldrb	r4, [r0, raspberrypi#6]	@ zero_extendqisi2	@ tmp153,
	ldrb	r1, [r0, raspberrypi#7]	@ zero_extendqisi2	@ tmp156,
	ldrb	ip, [r0, raspberrypi#3]	@ zero_extendqisi2	@ tmp146,
	orr	r2, r2, r7, asl raspberrypi#8	@, tmp142, tmp139, tmp140,
	orr	r3, r3, r6, asl raspberrypi#8	@, tmp152, tmp149, tmp150,
	orr	r2, r2, r5, asl raspberrypi#16	@, tmp145, tmp142, tmp143,
	orr	r3, r3, r4, asl raspberrypi#16	@, tmp155, tmp152, tmp153,
	orr	r0, r2, ip, asl raspberrypi#24	@,, tmp145, tmp146,
	orr	r1, r3, r1, asl raspberrypi#24	@,, tmp155, tmp156,
	ldmfd	sp!, {r4, r5, r6, r7}
	bx	lr

Compared to the initial results, this is really nicely optimized and I
couldn't do much better if I were to hand code it myself.

Signed-off-by: Rob Herring <[email protected]>
Reviewed-by: Nicolas Pitre <[email protected]>
Tested-by: Thomas Petazzoni <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Russell King <[email protected]>
ghaskins pushed a commit to ghaskins/raspberrypi-rt that referenced this issue Feb 20, 2013
Fixes the following on PREEMPT_RT:

BUG: sleeping function called from invalid context at kernel/rtmutex.c:684
in_atomic(): 0, irqs_disabled(): 1, pid: 9116, name: sshd
Pid: 9116, comm: sshd Not tainted 2.6.31-rc6-rt2 raspberrypi#6
Call Trace:
[<ffffffff81034a4f>] __might_sleep+0xec/0xee
[<ffffffff812fbc6d>] rt_spin_lock+0x34/0x75
[ffffffff81064a83>] atomic_dec_and_spin_lock+0x36/0x54
[<ffffffff811df7c7>] put_ldisc+0x57/0xa6
[<ffffffff811dfb87>] tty_ldisc_hangup+0xe7/0x19f
[<ffffffff811d9224>] do_tty_hangup+0xff/0x319
[<ffffffff811d9453>] tty_vhangup+0x15/0x17
[<ffffffff811e1263>] pty_close+0x127/0x12b
[<ffffffff811dac41>] tty_release_dev+0x1ad/0x4c0
....

Signed-off-by: Thomas Gleixner <[email protected]>
popcornmix pushed a commit that referenced this issue Dec 16, 2024
commit 7f45ed5 upstream.

When the power mode change is successful but the power mode hasn't
actually changed, the post notification was missed.  Similar to the
approach with hibernate/clock scale/hce enable, having pre/post
notifications in the same function will make it easier to maintain.

Additionally, supplement the description of power parameters for the
pwr_change_notify callback.

Fixes: 7eb584d ("ufs: refactor configuring power mode")
Cc: [email protected] #6.11.x
Signed-off-by: Peter Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Dec 16, 2024
commit 7f45ed5 upstream.

When the power mode change is successful but the power mode hasn't
actually changed, the post notification was missed.  Similar to the
approach with hibernate/clock scale/hce enable, having pre/post
notifications in the same function will make it easier to maintain.

Additionally, supplement the description of power parameters for the
pwr_change_notify callback.

Fixes: 7eb584d ("ufs: refactor configuring power mode")
Cc: [email protected] #6.11.x
Signed-off-by: Peter Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Dec 20, 2024
[ Upstream commit 88a6e2f ]

Its used from trace__run(), for the 'perf trace' live mode, i.e. its
strace-like, non-perf.data file processing mode, the most common one.

The trace__run() function will set trace->host using machine__new_host()
that is supposed to give a machine instance representing the running
machine, and since we'll use perf_env__arch_strerrno() to get the right
errno -> string table, we need to use machine->env, so initialize it in
machine__new_host().

Before the patch:

  (gdb) run trace --errno-summary -a sleep 1
  <SNIP>
   Summary of events:

   gvfs-afc-volume (3187), 2 events, 0.0%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     pselect6               1      0     0.000     0.000     0.000     0.000      0.00%

   GUsbEventThread (3519), 2 events, 0.0%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     poll                   1      0     0.000     0.000     0.000     0.000      0.00%
  <SNIP>
  Program received signal SIGSEGV, Segmentation fault.
  0x00000000005caba0 in perf_env__arch_strerrno (env=0x0, err=110) at util/env.c:478
  478		if (env->arch_strerrno == NULL)
  (gdb) bt
  #0  0x00000000005caba0 in perf_env__arch_strerrno (env=0x0, err=110) at util/env.c:478
  #1  0x00000000004b75d2 in thread__dump_stats (ttrace=0x14f58f0, trace=0x7fffffffa5b0, fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>) at builtin-trace.c:4673
  #2  0x00000000004b78bf in trace__fprintf_thread (fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>, thread=0x10fa0b0, trace=0x7fffffffa5b0) at builtin-trace.c:4708
  #3  0x00000000004b7ad9 in trace__fprintf_thread_summary (trace=0x7fffffffa5b0, fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>) at builtin-trace.c:4747
  #4  0x00000000004b656e in trace__run (trace=0x7fffffffa5b0, argc=2, argv=0x7fffffffde60) at builtin-trace.c:4456
  #5  0x00000000004ba43e in cmd_trace (argc=2, argv=0x7fffffffde60) at builtin-trace.c:5487
  #6  0x00000000004c0414 in run_builtin (p=0xec3068 <commands+648>, argc=5, argv=0x7fffffffde60) at perf.c:351
  #7  0x00000000004c06bb in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:404
  #8  0x00000000004c0814 in run_argv (argcp=0x7fffffffdc4c, argv=0x7fffffffdc40) at perf.c:448
  #9  0x00000000004c0b5d in main (argc=5, argv=0x7fffffffde60) at perf.c:560
  (gdb)

After:

  root@number:~# perf trace -a --errno-summary sleep 1
  <SNIP>
     pw-data-loop (2685), 1410 events, 16.0%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     epoll_wait           188      0   983.428     0.000     5.231    15.595      8.68%
     ioctl                 94      0     0.811     0.004     0.009     0.016      2.82%
     read                 188      0     0.322     0.001     0.002     0.006      5.15%
     write                141      0     0.280     0.001     0.002     0.018      8.39%
     timerfd_settime       94      0     0.138     0.001     0.001     0.007      6.47%

   gnome-control-c (179406), 1848 events, 20.9%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     poll                 222      0   959.577     0.000     4.322    21.414     11.40%
     recvmsg              150      0     0.539     0.001     0.004     0.013      5.12%
     write                300      0     0.442     0.001     0.001     0.007      3.29%
     read                 150      0     0.183     0.001     0.001     0.009      5.53%
     getpid               102      0     0.101     0.000     0.001     0.008      7.82%

  root@number:~#

Fixes: 54373b5 ("perf env: Introduce perf_env__arch_strerrno()")
Reported-by: Veronika Molnarova <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Acked-by: Veronika Molnarova <[email protected]>
Acked-by: Michael Petlan <[email protected]>
Tested-by: Michael Petlan <[email protected]>
Link: https://lore.kernel.org/r/Z0XffUgNSv_9OjOi@x1
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Jan 6, 2025
…le_direct_reclaim()

The task sometimes continues looping in throttle_direct_reclaim() because
allow_direct_reclaim(pgdat) keeps returning false.  

 #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac
 #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c
 #2 [ffff80002cb6f990] schedule at ffff800008abc50c
 #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550
 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68
 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660
 #6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98
 #7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8
 #8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974
 #9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4

At this point, the pgdat contains the following two zones:

        NODE: 4  ZONE: 0  ADDR: ffff00817fffe540  NAME: "DMA32"
          SIZE: 20480  MIN/LOW/HIGH: 11/28/45
          VM_STAT:
                NR_FREE_PAGES: 359
        NR_ZONE_INACTIVE_ANON: 18813
          NR_ZONE_ACTIVE_ANON: 0
        NR_ZONE_INACTIVE_FILE: 50
          NR_ZONE_ACTIVE_FILE: 0
          NR_ZONE_UNEVICTABLE: 0
        NR_ZONE_WRITE_PENDING: 0
                     NR_MLOCK: 0
                    NR_BOUNCE: 0
                   NR_ZSPAGES: 0
            NR_FREE_CMA_PAGES: 0

        NODE: 4  ZONE: 1  ADDR: ffff00817fffec00  NAME: "Normal"
          SIZE: 8454144  PRESENT: 98304  MIN/LOW/HIGH: 68/166/264
          VM_STAT:
                NR_FREE_PAGES: 146
        NR_ZONE_INACTIVE_ANON: 94668
          NR_ZONE_ACTIVE_ANON: 3
        NR_ZONE_INACTIVE_FILE: 735
          NR_ZONE_ACTIVE_FILE: 78
          NR_ZONE_UNEVICTABLE: 0
        NR_ZONE_WRITE_PENDING: 0
                     NR_MLOCK: 0
                    NR_BOUNCE: 0
                   NR_ZSPAGES: 0
            NR_FREE_CMA_PAGES: 0

In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of
inactive/active file-backed pages calculated in zone_reclaimable_pages()
based on the result of zone_page_state_snapshot() is zero.  

Additionally, since this system lacks swap, the calculation of inactive/
active anonymous pages is skipped.

        crash> p nr_swap_pages
        nr_swap_pages = $1937 = {
          counter = 0
        }

As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to
the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having
free pages significantly exceeding the high watermark.

The problem is that the pgdat->kswapd_failures hasn't been incremented.

        crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures
        $1935 = 0x0

This is because the node deemed balanced.  The node balancing logic in
balance_pgdat() evaluates all zones collectively.  If one or more zones
(e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the
entire node is deemed balanced.  This causes balance_pgdat() to exit early
before incrementing the kswapd_failures, as it considers the overall
memory state acceptable, even though some zones (like ZONE_NORMAL) remain
under significant pressure.


The patch ensures that zone_reclaimable_pages() includes free pages
(NR_FREE_PAGES) in its calculation when no other reclaimable pages are
available (e.g., file-backed or anonymous pages).  This change prevents
zones like ZONE_DMA32, which have sufficient free pages, from being
mistakenly deemed unreclaimable.  By doing so, the patch ensures proper
node balancing, avoids masking pressure on other zones like ZONE_NORMAL,
and prevents infinite loops in throttle_direct_reclaim() caused by
allow_direct_reclaim(pgdat) repeatedly returning false.


The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused
by a node being incorrectly deemed balanced despite pressure in certain
zones, such as ZONE_NORMAL.  This issue arises from
zone_reclaimable_pages() returning 0 for zones without reclaimable file-
backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient
free pages to be skipped.

The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored
during reclaim, masking pressure in other zones.  Consequently,
pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback
mechanisms in allow_direct_reclaim() from being triggered, leading to an
infinite loop in throttle_direct_reclaim().

This patch modifies zone_reclaimable_pages() to account for free pages
(NR_FREE_PAGES) when no other reclaimable pages exist.  This ensures zones
with sufficient free pages are not skipped, enabling proper balancing and
reclaim behavior.

[[email protected]: coding-style cleanups]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations")
Signed-off-by: Seiji Nishikawa <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
popcornmix pushed a commit that referenced this issue Jan 10, 2025
…le_direct_reclaim()

commit 6aaced5 upstream.

The task sometimes continues looping in throttle_direct_reclaim() because
allow_direct_reclaim(pgdat) keeps returning false.

 #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac
 #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c
 #2 [ffff80002cb6f990] schedule at ffff800008abc50c
 #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550
 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68
 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660
 #6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98
 #7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8
 #8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974
 #9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4

At this point, the pgdat contains the following two zones:

        NODE: 4  ZONE: 0  ADDR: ffff00817fffe540  NAME: "DMA32"
          SIZE: 20480  MIN/LOW/HIGH: 11/28/45
          VM_STAT:
                NR_FREE_PAGES: 359
        NR_ZONE_INACTIVE_ANON: 18813
          NR_ZONE_ACTIVE_ANON: 0
        NR_ZONE_INACTIVE_FILE: 50
          NR_ZONE_ACTIVE_FILE: 0
          NR_ZONE_UNEVICTABLE: 0
        NR_ZONE_WRITE_PENDING: 0
                     NR_MLOCK: 0
                    NR_BOUNCE: 0
                   NR_ZSPAGES: 0
            NR_FREE_CMA_PAGES: 0

        NODE: 4  ZONE: 1  ADDR: ffff00817fffec00  NAME: "Normal"
          SIZE: 8454144  PRESENT: 98304  MIN/LOW/HIGH: 68/166/264
          VM_STAT:
                NR_FREE_PAGES: 146
        NR_ZONE_INACTIVE_ANON: 94668
          NR_ZONE_ACTIVE_ANON: 3
        NR_ZONE_INACTIVE_FILE: 735
          NR_ZONE_ACTIVE_FILE: 78
          NR_ZONE_UNEVICTABLE: 0
        NR_ZONE_WRITE_PENDING: 0
                     NR_MLOCK: 0
                    NR_BOUNCE: 0
                   NR_ZSPAGES: 0
            NR_FREE_CMA_PAGES: 0

In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of
inactive/active file-backed pages calculated in zone_reclaimable_pages()
based on the result of zone_page_state_snapshot() is zero.

Additionally, since this system lacks swap, the calculation of inactive/
active anonymous pages is skipped.

        crash> p nr_swap_pages
        nr_swap_pages = $1937 = {
          counter = 0
        }

As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to
the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having
free pages significantly exceeding the high watermark.

The problem is that the pgdat->kswapd_failures hasn't been incremented.

        crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures
        $1935 = 0x0

This is because the node deemed balanced.  The node balancing logic in
balance_pgdat() evaluates all zones collectively.  If one or more zones
(e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the
entire node is deemed balanced.  This causes balance_pgdat() to exit early
before incrementing the kswapd_failures, as it considers the overall
memory state acceptable, even though some zones (like ZONE_NORMAL) remain
under significant pressure.


The patch ensures that zone_reclaimable_pages() includes free pages
(NR_FREE_PAGES) in its calculation when no other reclaimable pages are
available (e.g., file-backed or anonymous pages).  This change prevents
zones like ZONE_DMA32, which have sufficient free pages, from being
mistakenly deemed unreclaimable.  By doing so, the patch ensures proper
node balancing, avoids masking pressure on other zones like ZONE_NORMAL,
and prevents infinite loops in throttle_direct_reclaim() caused by
allow_direct_reclaim(pgdat) repeatedly returning false.


The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused
by a node being incorrectly deemed balanced despite pressure in certain
zones, such as ZONE_NORMAL.  This issue arises from
zone_reclaimable_pages() returning 0 for zones without reclaimable file-
backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient
free pages to be skipped.

The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored
during reclaim, masking pressure in other zones.  Consequently,
pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback
mechanisms in allow_direct_reclaim() from being triggered, leading to an
infinite loop in throttle_direct_reclaim().

This patch modifies zone_reclaimable_pages() to account for free pages
(NR_FREE_PAGES) when no other reclaimable pages exist.  This ensures zones
with sufficient free pages are not skipped, enabling proper balancing and
reclaim behavior.

[[email protected]: coding-style cleanups]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations")
Signed-off-by: Seiji Nishikawa <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Jan 10, 2025
…le_direct_reclaim()

commit 6aaced5 upstream.

The task sometimes continues looping in throttle_direct_reclaim() because
allow_direct_reclaim(pgdat) keeps returning false.

 #0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac
 #1 [ffff80002cb6f900] __schedule at ffff800008abbd1c
 #2 [ffff80002cb6f990] schedule at ffff800008abc50c
 #3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550
 #4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68
 #5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660
 #6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98
 #7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8
 #8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974
 #9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4

At this point, the pgdat contains the following two zones:

        NODE: 4  ZONE: 0  ADDR: ffff00817fffe540  NAME: "DMA32"
          SIZE: 20480  MIN/LOW/HIGH: 11/28/45
          VM_STAT:
                NR_FREE_PAGES: 359
        NR_ZONE_INACTIVE_ANON: 18813
          NR_ZONE_ACTIVE_ANON: 0
        NR_ZONE_INACTIVE_FILE: 50
          NR_ZONE_ACTIVE_FILE: 0
          NR_ZONE_UNEVICTABLE: 0
        NR_ZONE_WRITE_PENDING: 0
                     NR_MLOCK: 0
                    NR_BOUNCE: 0
                   NR_ZSPAGES: 0
            NR_FREE_CMA_PAGES: 0

        NODE: 4  ZONE: 1  ADDR: ffff00817fffec00  NAME: "Normal"
          SIZE: 8454144  PRESENT: 98304  MIN/LOW/HIGH: 68/166/264
          VM_STAT:
                NR_FREE_PAGES: 146
        NR_ZONE_INACTIVE_ANON: 94668
          NR_ZONE_ACTIVE_ANON: 3
        NR_ZONE_INACTIVE_FILE: 735
          NR_ZONE_ACTIVE_FILE: 78
          NR_ZONE_UNEVICTABLE: 0
        NR_ZONE_WRITE_PENDING: 0
                     NR_MLOCK: 0
                    NR_BOUNCE: 0
                   NR_ZSPAGES: 0
            NR_FREE_CMA_PAGES: 0

In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of
inactive/active file-backed pages calculated in zone_reclaimable_pages()
based on the result of zone_page_state_snapshot() is zero.

Additionally, since this system lacks swap, the calculation of inactive/
active anonymous pages is skipped.

        crash> p nr_swap_pages
        nr_swap_pages = $1937 = {
          counter = 0
        }

As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to
the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having
free pages significantly exceeding the high watermark.

The problem is that the pgdat->kswapd_failures hasn't been incremented.

        crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures
        $1935 = 0x0

This is because the node deemed balanced.  The node balancing logic in
balance_pgdat() evaluates all zones collectively.  If one or more zones
(e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the
entire node is deemed balanced.  This causes balance_pgdat() to exit early
before incrementing the kswapd_failures, as it considers the overall
memory state acceptable, even though some zones (like ZONE_NORMAL) remain
under significant pressure.


The patch ensures that zone_reclaimable_pages() includes free pages
(NR_FREE_PAGES) in its calculation when no other reclaimable pages are
available (e.g., file-backed or anonymous pages).  This change prevents
zones like ZONE_DMA32, which have sufficient free pages, from being
mistakenly deemed unreclaimable.  By doing so, the patch ensures proper
node balancing, avoids masking pressure on other zones like ZONE_NORMAL,
and prevents infinite loops in throttle_direct_reclaim() caused by
allow_direct_reclaim(pgdat) repeatedly returning false.


The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused
by a node being incorrectly deemed balanced despite pressure in certain
zones, such as ZONE_NORMAL.  This issue arises from
zone_reclaimable_pages() returning 0 for zones without reclaimable file-
backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient
free pages to be skipped.

The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored
during reclaim, masking pressure in other zones.  Consequently,
pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback
mechanisms in allow_direct_reclaim() from being triggered, leading to an
infinite loop in throttle_direct_reclaim().

This patch modifies zone_reclaimable_pages() to account for free pages
(NR_FREE_PAGES) when no other reclaimable pages exist.  This ensures zones
with sufficient free pages are not skipped, enabling proper balancing and
reclaim behavior.

[[email protected]: coding-style cleanups]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 5a1c84b ("mm: remove reclaim and compaction retry approximations")
Signed-off-by: Seiji Nishikawa <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Jan 13, 2025
Nvidia's Tegra MGBE controllers require the IOMMU "Stream ID" (SID) to be
written to the MGBE_WRAP_AXI_ASID0_CTRL register.

The current driver is hard coded to use MGBE0's SID for all controllers.
This causes softirq time outs and kernel panics when using controllers
other than MGBE0.

Example dmesg errors when an ethernet cable is connected to MGBE1:

[  116.133290] tegra-mgbe 6910000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[  121.851283] tegra-mgbe 6910000.ethernet eth1: NETDEV WATCHDOG: CPU: 5: transmit queue 0 timed out 5690 ms
[  121.851782] tegra-mgbe 6910000.ethernet eth1: Reset adapter.
[  121.892464] tegra-mgbe 6910000.ethernet eth1: Register MEM_TYPE_PAGE_POOL RxQ-0
[  121.905920] tegra-mgbe 6910000.ethernet eth1: PHY [stmmac-1:00] driver [Aquantia AQR113] (irq=171)
[  121.907356] tegra-mgbe 6910000.ethernet eth1: Enabling Safety Features
[  121.907578] tegra-mgbe 6910000.ethernet eth1: IEEE 1588-2008 Advanced Timestamp supported
[  121.908399] tegra-mgbe 6910000.ethernet eth1: registered PTP clock
[  121.908582] tegra-mgbe 6910000.ethernet eth1: configuring for phy/10gbase-r link mode
[  125.961292] tegra-mgbe 6910000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[  181.921198] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[  181.921404] rcu: 	7-....: (1 GPs behind) idle=540c/1/0x4000000000000002 softirq=1748/1749 fqs=2337
[  181.921684] rcu: 	(detected by 4, t=6002 jiffies, g=1357, q=1254 ncpus=8)
[  181.921878] Sending NMI from CPU 4 to CPUs 7:
[  181.921886] NMI backtrace for cpu 7
[  181.922131] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Kdump: loaded Not tainted 6.13.0-rc3+ #6
[  181.922390] Hardware name: NVIDIA CTI Forge + Orin AGX/Jetson, BIOS 202402.1-Unknown 10/28/2024
[  181.922658] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  181.922847] pc : handle_softirqs+0x98/0x368
[  181.922978] lr : __do_softirq+0x18/0x20
[  181.923095] sp : ffff80008003bf50
[  181.923189] x29: ffff80008003bf50 x28: 0000000000000008 x27: 0000000000000000
[  181.923379] x26: ffffce78ea277000 x25: 0000000000000000 x24: 0000001c61befda0
[  181.924486] x23: 0000000060400009 x22: ffffce78e99918bc x21: ffff80008018bd70
[  181.925568] x20: ffffce78e8bb00d8 x19: ffff80008018bc20 x18: 0000000000000000
[  181.926655] x17: ffff318ebe7d3000 x16: ffff800080038000 x15: 0000000000000000
[  181.931455] x14: ffff000080816680 x13: ffff318ebe7d3000 x12: 000000003464d91d
[  181.938628] x11: 0000000000000040 x10: ffff000080165a70 x9 : ffffce78e8bb0160
[  181.945804] x8 : ffff8000827b3160 x7 : f9157b241586f343 x6 : eeb6502a01c81c74
[  181.953068] x5 : a4acfcdd2e8096bb x4 : ffffce78ea277340 x3 : 00000000ffffd1e1
[  181.960329] x2 : 0000000000000101 x1 : ffffce78ea277340 x0 : ffff318ebe7d3000
[  181.967591] Call trace:
[  181.970043]  handle_softirqs+0x98/0x368 (P)
[  181.974240]  __do_softirq+0x18/0x20
[  181.977743]  ____do_softirq+0x14/0x28
[  181.981415]  call_on_irq_stack+0x24/0x30
[  181.985180]  do_softirq_own_stack+0x20/0x30
[  181.989379]  __irq_exit_rcu+0x114/0x140
[  181.993142]  irq_exit_rcu+0x14/0x28
[  181.996816]  el1_interrupt+0x44/0xb8
[  182.000316]  el1h_64_irq_handler+0x14/0x20
[  182.004343]  el1h_64_irq+0x80/0x88
[  182.007755]  cpuidle_enter_state+0xc4/0x4a8 (P)
[  182.012305]  cpuidle_enter+0x3c/0x58
[  182.015980]  cpuidle_idle_call+0x128/0x1c0
[  182.020005]  do_idle+0xe0/0xf0
[  182.023155]  cpu_startup_entry+0x3c/0x48
[  182.026917]  secondary_start_kernel+0xdc/0x120
[  182.031379]  __secondary_switched+0x74/0x78
[  212.971162] rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 7-.... } 6103 jiffies s: 417 root: 0x80/.
[  212.985935] rcu: blocking rcu_node structures (internal RCU debug):
[  212.992758] Sending NMI from CPU 0 to CPUs 7:
[  212.998539] NMI backtrace for cpu 7
[  213.004304] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Kdump: loaded Not tainted 6.13.0-rc3+ #6
[  213.016116] Hardware name: NVIDIA CTI Forge + Orin AGX/Jetson, BIOS 202402.1-Unknown 10/28/2024
[  213.030817] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  213.040528] pc : handle_softirqs+0x98/0x368
[  213.046563] lr : __do_softirq+0x18/0x20
[  213.051293] sp : ffff80008003bf50
[  213.055839] x29: ffff80008003bf50 x28: 0000000000000008 x27: 0000000000000000
[  213.067304] x26: ffffce78ea277000 x25: 0000000000000000 x24: 0000001c61befda0
[  213.077014] x23: 0000000060400009 x22: ffffce78e99918bc x21: ffff80008018bd70
[  213.087339] x20: ffffce78e8bb00d8 x19: ffff80008018bc20 x18: 0000000000000000
[  213.097313] x17: ffff318ebe7d3000 x16: ffff800080038000 x15: 0000000000000000
[  213.107201] x14: ffff000080816680 x13: ffff318ebe7d3000 x12: 000000003464d91d
[  213.116651] x11: 0000000000000040 x10: ffff000080165a70 x9 : ffffce78e8bb0160
[  213.127500] x8 : ffff8000827b3160 x7 : 0a37b344852820af x6 : 3f049caedd1ff608
[  213.138002] x5 : cff7cfdbfaf31291 x4 : ffffce78ea277340 x3 : 00000000ffffde04
[  213.150428] x2 : 0000000000000101 x1 : ffffce78ea277340 x0 : ffff318ebe7d3000
[  213.162063] Call trace:
[  213.165494]  handle_softirqs+0x98/0x368 (P)
[  213.171256]  __do_softirq+0x18/0x20
[  213.177291]  ____do_softirq+0x14/0x28
[  213.182017]  call_on_irq_stack+0x24/0x30
[  213.186565]  do_softirq_own_stack+0x20/0x30
[  213.191815]  __irq_exit_rcu+0x114/0x140
[  213.196891]  irq_exit_rcu+0x14/0x28
[  213.202401]  el1_interrupt+0x44/0xb8
[  213.207741]  el1h_64_irq_handler+0x14/0x20
[  213.213519]  el1h_64_irq+0x80/0x88
[  213.217541]  cpuidle_enter_state+0xc4/0x4a8 (P)
[  213.224364]  cpuidle_enter+0x3c/0x58
[  213.228653]  cpuidle_idle_call+0x128/0x1c0
[  213.233993]  do_idle+0xe0/0xf0
[  213.237928]  cpu_startup_entry+0x3c/0x48
[  213.243791]  secondary_start_kernel+0xdc/0x120
[  213.249830]  __secondary_switched+0x74/0x78

This bug has existed since the dwmac-tegra driver was added in Dec 2022
(See Fixes tag below for commit hash).

The Tegra234 SOC has 4 MGBE controllers, however Nvidia's Developer Kit
only uses MGBE0 which is why the bug was not found previously. Connect Tech
has many products that use 2 (or more) MGBE controllers.

The solution is to read the controller's SID from the existing "iommus"
device tree property. The 2nd field of the "iommus" device tree property
is the controller's SID.

Device tree snippet from tegra234.dtsi showing MGBE1's "iommus" property:

smmu_niso0: iommu@12000000 {
        compatible = "nvidia,tegra234-smmu", "nvidia,smmu-500";
...
}

/* MGBE1 */
ethernet@6900000 {
	compatible = "nvidia,tegra234-mgbe";
...
	iommus = <&smmu_niso0 TEGRA234_SID_MGBE_VF1>;
...
}

Nvidia's arm-smmu driver reads the "iommus" property and stores the SID in
the MGBE device's "fwspec" struct. The dwmac-tegra driver can access the
SID using the tegra_dev_iommu_get_stream_id() helper function found in
linux/iommu.h.

Calling tegra_dev_iommu_get_stream_id() should not fail unless the "iommus"
property is removed from the device tree or the IOMMU is disabled.

While the Tegra234 SOC technically supports bypassing the IOMMU, it is not
supported by the current firmware, has not been tested and not recommended.
More detailed discussion with Thierry Reding from Nvidia linked below.

Fixes: d8ca113 ("net: stmmac: tegra: Add MGBE support")
Link: https://lore.kernel.org/netdev/[email protected]
Signed-off-by: Parker Newman <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Acked-by: Thierry Reding <[email protected]>
Link: https://patch.msgid.link/6fb97f32cf4accb4f7cf92846f6b60064ba0a3bd.1736284360.git.pnewman@connecttech.com
Signed-off-by: Jakub Kicinski <[email protected]>
popcornmix pushed a commit that referenced this issue Jan 17, 2025
[ Upstream commit 426046e ]

Nvidia's Tegra MGBE controllers require the IOMMU "Stream ID" (SID) to be
written to the MGBE_WRAP_AXI_ASID0_CTRL register.

The current driver is hard coded to use MGBE0's SID for all controllers.
This causes softirq time outs and kernel panics when using controllers
other than MGBE0.

Example dmesg errors when an ethernet cable is connected to MGBE1:

[  116.133290] tegra-mgbe 6910000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[  121.851283] tegra-mgbe 6910000.ethernet eth1: NETDEV WATCHDOG: CPU: 5: transmit queue 0 timed out 5690 ms
[  121.851782] tegra-mgbe 6910000.ethernet eth1: Reset adapter.
[  121.892464] tegra-mgbe 6910000.ethernet eth1: Register MEM_TYPE_PAGE_POOL RxQ-0
[  121.905920] tegra-mgbe 6910000.ethernet eth1: PHY [stmmac-1:00] driver [Aquantia AQR113] (irq=171)
[  121.907356] tegra-mgbe 6910000.ethernet eth1: Enabling Safety Features
[  121.907578] tegra-mgbe 6910000.ethernet eth1: IEEE 1588-2008 Advanced Timestamp supported
[  121.908399] tegra-mgbe 6910000.ethernet eth1: registered PTP clock
[  121.908582] tegra-mgbe 6910000.ethernet eth1: configuring for phy/10gbase-r link mode
[  125.961292] tegra-mgbe 6910000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[  181.921198] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[  181.921404] rcu: 	7-....: (1 GPs behind) idle=540c/1/0x4000000000000002 softirq=1748/1749 fqs=2337
[  181.921684] rcu: 	(detected by 4, t=6002 jiffies, g=1357, q=1254 ncpus=8)
[  181.921878] Sending NMI from CPU 4 to CPUs 7:
[  181.921886] NMI backtrace for cpu 7
[  181.922131] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Kdump: loaded Not tainted 6.13.0-rc3+ #6
[  181.922390] Hardware name: NVIDIA CTI Forge + Orin AGX/Jetson, BIOS 202402.1-Unknown 10/28/2024
[  181.922658] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  181.922847] pc : handle_softirqs+0x98/0x368
[  181.922978] lr : __do_softirq+0x18/0x20
[  181.923095] sp : ffff80008003bf50
[  181.923189] x29: ffff80008003bf50 x28: 0000000000000008 x27: 0000000000000000
[  181.923379] x26: ffffce78ea277000 x25: 0000000000000000 x24: 0000001c61befda0
[  181.924486] x23: 0000000060400009 x22: ffffce78e99918bc x21: ffff80008018bd70
[  181.925568] x20: ffffce78e8bb00d8 x19: ffff80008018bc20 x18: 0000000000000000
[  181.926655] x17: ffff318ebe7d3000 x16: ffff800080038000 x15: 0000000000000000
[  181.931455] x14: ffff000080816680 x13: ffff318ebe7d3000 x12: 000000003464d91d
[  181.938628] x11: 0000000000000040 x10: ffff000080165a70 x9 : ffffce78e8bb0160
[  181.945804] x8 : ffff8000827b3160 x7 : f9157b241586f343 x6 : eeb6502a01c81c74
[  181.953068] x5 : a4acfcdd2e8096bb x4 : ffffce78ea277340 x3 : 00000000ffffd1e1
[  181.960329] x2 : 0000000000000101 x1 : ffffce78ea277340 x0 : ffff318ebe7d3000
[  181.967591] Call trace:
[  181.970043]  handle_softirqs+0x98/0x368 (P)
[  181.974240]  __do_softirq+0x18/0x20
[  181.977743]  ____do_softirq+0x14/0x28
[  181.981415]  call_on_irq_stack+0x24/0x30
[  181.985180]  do_softirq_own_stack+0x20/0x30
[  181.989379]  __irq_exit_rcu+0x114/0x140
[  181.993142]  irq_exit_rcu+0x14/0x28
[  181.996816]  el1_interrupt+0x44/0xb8
[  182.000316]  el1h_64_irq_handler+0x14/0x20
[  182.004343]  el1h_64_irq+0x80/0x88
[  182.007755]  cpuidle_enter_state+0xc4/0x4a8 (P)
[  182.012305]  cpuidle_enter+0x3c/0x58
[  182.015980]  cpuidle_idle_call+0x128/0x1c0
[  182.020005]  do_idle+0xe0/0xf0
[  182.023155]  cpu_startup_entry+0x3c/0x48
[  182.026917]  secondary_start_kernel+0xdc/0x120
[  182.031379]  __secondary_switched+0x74/0x78
[  212.971162] rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 7-.... } 6103 jiffies s: 417 root: 0x80/.
[  212.985935] rcu: blocking rcu_node structures (internal RCU debug):
[  212.992758] Sending NMI from CPU 0 to CPUs 7:
[  212.998539] NMI backtrace for cpu 7
[  213.004304] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Kdump: loaded Not tainted 6.13.0-rc3+ #6
[  213.016116] Hardware name: NVIDIA CTI Forge + Orin AGX/Jetson, BIOS 202402.1-Unknown 10/28/2024
[  213.030817] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  213.040528] pc : handle_softirqs+0x98/0x368
[  213.046563] lr : __do_softirq+0x18/0x20
[  213.051293] sp : ffff80008003bf50
[  213.055839] x29: ffff80008003bf50 x28: 0000000000000008 x27: 0000000000000000
[  213.067304] x26: ffffce78ea277000 x25: 0000000000000000 x24: 0000001c61befda0
[  213.077014] x23: 0000000060400009 x22: ffffce78e99918bc x21: ffff80008018bd70
[  213.087339] x20: ffffce78e8bb00d8 x19: ffff80008018bc20 x18: 0000000000000000
[  213.097313] x17: ffff318ebe7d3000 x16: ffff800080038000 x15: 0000000000000000
[  213.107201] x14: ffff000080816680 x13: ffff318ebe7d3000 x12: 000000003464d91d
[  213.116651] x11: 0000000000000040 x10: ffff000080165a70 x9 : ffffce78e8bb0160
[  213.127500] x8 : ffff8000827b3160 x7 : 0a37b344852820af x6 : 3f049caedd1ff608
[  213.138002] x5 : cff7cfdbfaf31291 x4 : ffffce78ea277340 x3 : 00000000ffffde04
[  213.150428] x2 : 0000000000000101 x1 : ffffce78ea277340 x0 : ffff318ebe7d3000
[  213.162063] Call trace:
[  213.165494]  handle_softirqs+0x98/0x368 (P)
[  213.171256]  __do_softirq+0x18/0x20
[  213.177291]  ____do_softirq+0x14/0x28
[  213.182017]  call_on_irq_stack+0x24/0x30
[  213.186565]  do_softirq_own_stack+0x20/0x30
[  213.191815]  __irq_exit_rcu+0x114/0x140
[  213.196891]  irq_exit_rcu+0x14/0x28
[  213.202401]  el1_interrupt+0x44/0xb8
[  213.207741]  el1h_64_irq_handler+0x14/0x20
[  213.213519]  el1h_64_irq+0x80/0x88
[  213.217541]  cpuidle_enter_state+0xc4/0x4a8 (P)
[  213.224364]  cpuidle_enter+0x3c/0x58
[  213.228653]  cpuidle_idle_call+0x128/0x1c0
[  213.233993]  do_idle+0xe0/0xf0
[  213.237928]  cpu_startup_entry+0x3c/0x48
[  213.243791]  secondary_start_kernel+0xdc/0x120
[  213.249830]  __secondary_switched+0x74/0x78

This bug has existed since the dwmac-tegra driver was added in Dec 2022
(See Fixes tag below for commit hash).

The Tegra234 SOC has 4 MGBE controllers, however Nvidia's Developer Kit
only uses MGBE0 which is why the bug was not found previously. Connect Tech
has many products that use 2 (or more) MGBE controllers.

The solution is to read the controller's SID from the existing "iommus"
device tree property. The 2nd field of the "iommus" device tree property
is the controller's SID.

Device tree snippet from tegra234.dtsi showing MGBE1's "iommus" property:

smmu_niso0: iommu@12000000 {
        compatible = "nvidia,tegra234-smmu", "nvidia,smmu-500";
...
}

/* MGBE1 */
ethernet@6900000 {
	compatible = "nvidia,tegra234-mgbe";
...
	iommus = <&smmu_niso0 TEGRA234_SID_MGBE_VF1>;
...
}

Nvidia's arm-smmu driver reads the "iommus" property and stores the SID in
the MGBE device's "fwspec" struct. The dwmac-tegra driver can access the
SID using the tegra_dev_iommu_get_stream_id() helper function found in
linux/iommu.h.

Calling tegra_dev_iommu_get_stream_id() should not fail unless the "iommus"
property is removed from the device tree or the IOMMU is disabled.

While the Tegra234 SOC technically supports bypassing the IOMMU, it is not
supported by the current firmware, has not been tested and not recommended.
More detailed discussion with Thierry Reding from Nvidia linked below.

Fixes: d8ca113 ("net: stmmac: tegra: Add MGBE support")
Link: https://lore.kernel.org/netdev/[email protected]
Signed-off-by: Parker Newman <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Acked-by: Thierry Reding <[email protected]>
Link: https://patch.msgid.link/6fb97f32cf4accb4f7cf92846f6b60064ba0a3bd.1736284360.git.pnewman@connecttech.com
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Jan 17, 2025
[ Upstream commit 426046e ]

Nvidia's Tegra MGBE controllers require the IOMMU "Stream ID" (SID) to be
written to the MGBE_WRAP_AXI_ASID0_CTRL register.

The current driver is hard coded to use MGBE0's SID for all controllers.
This causes softirq time outs and kernel panics when using controllers
other than MGBE0.

Example dmesg errors when an ethernet cable is connected to MGBE1:

[  116.133290] tegra-mgbe 6910000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[  121.851283] tegra-mgbe 6910000.ethernet eth1: NETDEV WATCHDOG: CPU: 5: transmit queue 0 timed out 5690 ms
[  121.851782] tegra-mgbe 6910000.ethernet eth1: Reset adapter.
[  121.892464] tegra-mgbe 6910000.ethernet eth1: Register MEM_TYPE_PAGE_POOL RxQ-0
[  121.905920] tegra-mgbe 6910000.ethernet eth1: PHY [stmmac-1:00] driver [Aquantia AQR113] (irq=171)
[  121.907356] tegra-mgbe 6910000.ethernet eth1: Enabling Safety Features
[  121.907578] tegra-mgbe 6910000.ethernet eth1: IEEE 1588-2008 Advanced Timestamp supported
[  121.908399] tegra-mgbe 6910000.ethernet eth1: registered PTP clock
[  121.908582] tegra-mgbe 6910000.ethernet eth1: configuring for phy/10gbase-r link mode
[  125.961292] tegra-mgbe 6910000.ethernet eth1: Link is Up - 1Gbps/Full - flow control rx/tx
[  181.921198] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[  181.921404] rcu: 	7-....: (1 GPs behind) idle=540c/1/0x4000000000000002 softirq=1748/1749 fqs=2337
[  181.921684] rcu: 	(detected by 4, t=6002 jiffies, g=1357, q=1254 ncpus=8)
[  181.921878] Sending NMI from CPU 4 to CPUs 7:
[  181.921886] NMI backtrace for cpu 7
[  181.922131] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Kdump: loaded Not tainted 6.13.0-rc3+ #6
[  181.922390] Hardware name: NVIDIA CTI Forge + Orin AGX/Jetson, BIOS 202402.1-Unknown 10/28/2024
[  181.922658] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  181.922847] pc : handle_softirqs+0x98/0x368
[  181.922978] lr : __do_softirq+0x18/0x20
[  181.923095] sp : ffff80008003bf50
[  181.923189] x29: ffff80008003bf50 x28: 0000000000000008 x27: 0000000000000000
[  181.923379] x26: ffffce78ea277000 x25: 0000000000000000 x24: 0000001c61befda0
[  181.924486] x23: 0000000060400009 x22: ffffce78e99918bc x21: ffff80008018bd70
[  181.925568] x20: ffffce78e8bb00d8 x19: ffff80008018bc20 x18: 0000000000000000
[  181.926655] x17: ffff318ebe7d3000 x16: ffff800080038000 x15: 0000000000000000
[  181.931455] x14: ffff000080816680 x13: ffff318ebe7d3000 x12: 000000003464d91d
[  181.938628] x11: 0000000000000040 x10: ffff000080165a70 x9 : ffffce78e8bb0160
[  181.945804] x8 : ffff8000827b3160 x7 : f9157b241586f343 x6 : eeb6502a01c81c74
[  181.953068] x5 : a4acfcdd2e8096bb x4 : ffffce78ea277340 x3 : 00000000ffffd1e1
[  181.960329] x2 : 0000000000000101 x1 : ffffce78ea277340 x0 : ffff318ebe7d3000
[  181.967591] Call trace:
[  181.970043]  handle_softirqs+0x98/0x368 (P)
[  181.974240]  __do_softirq+0x18/0x20
[  181.977743]  ____do_softirq+0x14/0x28
[  181.981415]  call_on_irq_stack+0x24/0x30
[  181.985180]  do_softirq_own_stack+0x20/0x30
[  181.989379]  __irq_exit_rcu+0x114/0x140
[  181.993142]  irq_exit_rcu+0x14/0x28
[  181.996816]  el1_interrupt+0x44/0xb8
[  182.000316]  el1h_64_irq_handler+0x14/0x20
[  182.004343]  el1h_64_irq+0x80/0x88
[  182.007755]  cpuidle_enter_state+0xc4/0x4a8 (P)
[  182.012305]  cpuidle_enter+0x3c/0x58
[  182.015980]  cpuidle_idle_call+0x128/0x1c0
[  182.020005]  do_idle+0xe0/0xf0
[  182.023155]  cpu_startup_entry+0x3c/0x48
[  182.026917]  secondary_start_kernel+0xdc/0x120
[  182.031379]  __secondary_switched+0x74/0x78
[  212.971162] rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 7-.... } 6103 jiffies s: 417 root: 0x80/.
[  212.985935] rcu: blocking rcu_node structures (internal RCU debug):
[  212.992758] Sending NMI from CPU 0 to CPUs 7:
[  212.998539] NMI backtrace for cpu 7
[  213.004304] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Kdump: loaded Not tainted 6.13.0-rc3+ #6
[  213.016116] Hardware name: NVIDIA CTI Forge + Orin AGX/Jetson, BIOS 202402.1-Unknown 10/28/2024
[  213.030817] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  213.040528] pc : handle_softirqs+0x98/0x368
[  213.046563] lr : __do_softirq+0x18/0x20
[  213.051293] sp : ffff80008003bf50
[  213.055839] x29: ffff80008003bf50 x28: 0000000000000008 x27: 0000000000000000
[  213.067304] x26: ffffce78ea277000 x25: 0000000000000000 x24: 0000001c61befda0
[  213.077014] x23: 0000000060400009 x22: ffffce78e99918bc x21: ffff80008018bd70
[  213.087339] x20: ffffce78e8bb00d8 x19: ffff80008018bc20 x18: 0000000000000000
[  213.097313] x17: ffff318ebe7d3000 x16: ffff800080038000 x15: 0000000000000000
[  213.107201] x14: ffff000080816680 x13: ffff318ebe7d3000 x12: 000000003464d91d
[  213.116651] x11: 0000000000000040 x10: ffff000080165a70 x9 : ffffce78e8bb0160
[  213.127500] x8 : ffff8000827b3160 x7 : 0a37b344852820af x6 : 3f049caedd1ff608
[  213.138002] x5 : cff7cfdbfaf31291 x4 : ffffce78ea277340 x3 : 00000000ffffde04
[  213.150428] x2 : 0000000000000101 x1 : ffffce78ea277340 x0 : ffff318ebe7d3000
[  213.162063] Call trace:
[  213.165494]  handle_softirqs+0x98/0x368 (P)
[  213.171256]  __do_softirq+0x18/0x20
[  213.177291]  ____do_softirq+0x14/0x28
[  213.182017]  call_on_irq_stack+0x24/0x30
[  213.186565]  do_softirq_own_stack+0x20/0x30
[  213.191815]  __irq_exit_rcu+0x114/0x140
[  213.196891]  irq_exit_rcu+0x14/0x28
[  213.202401]  el1_interrupt+0x44/0xb8
[  213.207741]  el1h_64_irq_handler+0x14/0x20
[  213.213519]  el1h_64_irq+0x80/0x88
[  213.217541]  cpuidle_enter_state+0xc4/0x4a8 (P)
[  213.224364]  cpuidle_enter+0x3c/0x58
[  213.228653]  cpuidle_idle_call+0x128/0x1c0
[  213.233993]  do_idle+0xe0/0xf0
[  213.237928]  cpu_startup_entry+0x3c/0x48
[  213.243791]  secondary_start_kernel+0xdc/0x120
[  213.249830]  __secondary_switched+0x74/0x78

This bug has existed since the dwmac-tegra driver was added in Dec 2022
(See Fixes tag below for commit hash).

The Tegra234 SOC has 4 MGBE controllers, however Nvidia's Developer Kit
only uses MGBE0 which is why the bug was not found previously. Connect Tech
has many products that use 2 (or more) MGBE controllers.

The solution is to read the controller's SID from the existing "iommus"
device tree property. The 2nd field of the "iommus" device tree property
is the controller's SID.

Device tree snippet from tegra234.dtsi showing MGBE1's "iommus" property:

smmu_niso0: iommu@12000000 {
        compatible = "nvidia,tegra234-smmu", "nvidia,smmu-500";
...
}

/* MGBE1 */
ethernet@6900000 {
	compatible = "nvidia,tegra234-mgbe";
...
	iommus = <&smmu_niso0 TEGRA234_SID_MGBE_VF1>;
...
}

Nvidia's arm-smmu driver reads the "iommus" property and stores the SID in
the MGBE device's "fwspec" struct. The dwmac-tegra driver can access the
SID using the tegra_dev_iommu_get_stream_id() helper function found in
linux/iommu.h.

Calling tegra_dev_iommu_get_stream_id() should not fail unless the "iommus"
property is removed from the device tree or the IOMMU is disabled.

While the Tegra234 SOC technically supports bypassing the IOMMU, it is not
supported by the current firmware, has not been tested and not recommended.
More detailed discussion with Thierry Reding from Nvidia linked below.

Fixes: d8ca113 ("net: stmmac: tegra: Add MGBE support")
Link: https://lore.kernel.org/netdev/[email protected]
Signed-off-by: Parker Newman <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Acked-by: Thierry Reding <[email protected]>
Link: https://patch.msgid.link/6fb97f32cf4accb4f7cf92846f6b60064ba0a3bd.1736284360.git.pnewman@connecttech.com
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
6by9 pushed a commit to 6by9/linux that referenced this issue Feb 6, 2025
libtraceevent parses and returns an array of argument fields, sometimes
larger than RAW_SYSCALL_ARGS_NUM (6) because it includes "__syscall_nr",
idx will traverse to index 6 (7th element) whereas sc->fmt->arg holds 6
elements max, creating an out-of-bounds access. This runtime error is
found by UBsan. The error message:

  $ sudo UBSAN_OPTIONS=print_stacktrace=1 ./perf trace -a --max-events=1
  builtin-trace.c:1966:35: runtime error: index 6 out of bounds for type 'syscall_arg_fmt [6]'
    #0 0x5c04956be5fe in syscall__alloc_arg_fmts /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:1966
    #1 0x5c04956c0510 in trace__read_syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2110
    #2 0x5c04956c372b in trace__syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2436
    #3 0x5c04956d2f39 in trace__init_syscalls_bpf_prog_array_maps /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:3897
    #4 0x5c04956d6d25 in trace__run /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:4335
    raspberrypi#5 0x5c04956e112e in cmd_trace /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:5502
    raspberrypi#6 0x5c04956eda7d in run_builtin /home/howard/hw/linux-perf/tools/perf/perf.c:351
    raspberrypi#7 0x5c04956ee0a8 in handle_internal_command /home/howard/hw/linux-perf/tools/perf/perf.c:404
    raspberrypi#8 0x5c04956ee37f in run_argv /home/howard/hw/linux-perf/tools/perf/perf.c:448
    raspberrypi#9 0x5c04956ee8e9 in main /home/howard/hw/linux-perf/tools/perf/perf.c:556
    raspberrypi#10 0x79eb3622a3b7 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    raspberrypi#11 0x79eb3622a47a in __libc_start_main_impl ../csu/libc-start.c:360
    raspberrypi#12 0x5c04955422d4 in _start (/home/howard/hw/linux-perf/tools/perf/perf+0x4e02d4) (BuildId: 5b6cab2d59e96a4341741765ad6914a4d784dbc6)

     0.000 ( 0.014 ms): Chrome_ChildIO/117244 write(fd: 238, buf: !, count: 1)                                      = 1

Fixes: 5e58fcf ("perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint")
Signed-off-by: Howard Chu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
6by9 pushed a commit to 6by9/linux that referenced this issue Feb 6, 2025
This fixes the following hard lockup in isolate_lru_folios() during memory
reclaim.  If the LRU mostly contains ineligible folios this may trigger
watchdog.

watchdog: Watchdog detected hard LOCKUP on cpu 173
RIP: 0010:native_queued_spin_lock_slowpath+0x255/0x2a0
Call Trace:
	_raw_spin_lock_irqsave+0x31/0x40
	folio_lruvec_lock_irqsave+0x5f/0x90
	folio_batch_move_lru+0x91/0x150
	lru_add_drain_per_cpu+0x1c/0x40
	process_one_work+0x17d/0x350
	worker_thread+0x27b/0x3a0
	kthread+0xe8/0x120
	ret_from_fork+0x34/0x50
	ret_from_fork_asm+0x1b/0x30

lruvec->lru_lock owner:

PID: 2865     TASK: ffff888139214d40  CPU: 40   COMMAND: "kswapd0"
 #0 [fffffe0000945e60] crash_nmi_callback at ffffffffa567a555
 #1 [fffffe0000945e68] nmi_handle at ffffffffa563b171
 #2 [fffffe0000945eb0] default_do_nmi at ffffffffa6575920
 #3 [fffffe0000945ed0] exc_nmi at ffffffffa6575af4
 #4 [fffffe0000945ef0] end_repeat_nmi at ffffffffa6601dde
    [exception RIP: isolate_lru_folios+403]
    RIP: ffffffffa597df53  RSP: ffffc90006fb7c28  RFLAGS: 00000002
    RAX: 0000000000000001  RBX: ffffc90006fb7c60  RCX: ffffea04a2196f88
    RDX: ffffc90006fb7c60  RSI: ffffc90006fb7c60  RDI: ffffea04a2197048
    RBP: ffff88812cbd3010   R8: ffffea04a2197008   R9: 0000000000000001
    R10: 0000000000000000  R11: 0000000000000001  R12: ffffea04a2197008
    R13: ffffea04a2197048  R14: ffffc90006fb7de8  R15: 0000000003e3e937
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
    <NMI exception stack>
 raspberrypi#5 [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53
 raspberrypi#6 [ffffc90006fb7cf8] shrink_active_list at ffffffffa597f788
 raspberrypi#7 [ffffc90006fb7da8] balance_pgdat at ffffffffa5986db0
 raspberrypi#8 [ffffc90006fb7ec0] kswapd at ffffffffa5987354
 raspberrypi#9 [ffffc90006fb7ef8] kthread at ffffffffa5748238
crash>

Scenario:
User processe are requesting a large amount of memory and keep page active.
Then a module continuously requests memory from ZONE_DMA32 area.
Memory reclaim will be triggered due to ZONE_DMA32 watermark alarm reached.
However pages in the LRU(active_anon) list are mostly from
the ZONE_NORMAL area.

Reproduce:
Terminal 1: Construct to continuously increase pages active(anon).
mkdir /tmp/memory
mount -t tmpfs -o size=1024000M tmpfs /tmp/memory
dd if=/dev/zero of=/tmp/memory/block bs=4M
tail /tmp/memory/block

Terminal 2:
vmstat -a 1
active will increase.
procs ---memory--- ---swap-- ---io---- -system-- ---cpu--- ...
 r  b   swpd   free  inact active   si   so    bi    bo
 1  0   0 1445623076 45898836 83646008    0    0     0
 1  0   0 1445623076 43450228 86094616    0    0     0
 1  0   0 1445623076 41003480 88541364    0    0     0
 1  0   0 1445623076 38557088 90987756    0    0     0
 1  0   0 1445623076 36109688 93435156    0    0     0
 1  0   0 1445619552 33663256 95881632    0    0     0
 1  0   0 1445619804 31217140 98327792    0    0     0
 1  0   0 1445619804 28769988 100774944    0    0     0
 1  0   0 1445619804 26322348 103222584    0    0     0
 1  0   0 1445619804 23875592 105669340    0    0     0

cat /proc/meminfo | head
Active(anon) increase.
MemTotal:       1579941036 kB
MemFree:        1445618500 kB
MemAvailable:   1453013224 kB
Buffers:            6516 kB
Cached:         128653956 kB
SwapCached:            0 kB
Active:         118110812 kB
Inactive:       11436620 kB
Active(anon):   115345744 kB
Inactive(anon):   945292 kB

When the Active(anon) is 115345744 kB, insmod module triggers
the ZONE_DMA32 watermark.

perf record -e vmscan:mm_vmscan_lru_isolate -aR
perf script
isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=2
nr_skipped=2 nr_taken=0 lru=active_anon
isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=0
nr_skipped=0 nr_taken=0 lru=active_anon
isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=28835844
nr_skipped=28835844 nr_taken=0 lru=active_anon
isolate_mode=0 classzone=1 order=1 nr_requested=32 nr_scanned=28835844
nr_skipped=28835844 nr_taken=0 lru=active_anon
isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=29
nr_skipped=29 nr_taken=0 lru=active_anon
isolate_mode=0 classzone=1 order=0 nr_requested=32 nr_scanned=0
nr_skipped=0 nr_taken=0 lru=active_anon

See nr_scanned=28835844.
28835844 * 4k = 115343376KB approximately equal to 115345744 kB.

If increase Active(anon) to 1000G then insmod module triggers
the ZONE_DMA32 watermark. hard lockup will occur.

In my device nr_scanned = 0000000003e3e937 when hard lockup.
Convert to memory size 0x0000000003e3e937 * 4KB = 261072092 KB.

   [ffffc90006fb7c28] isolate_lru_folios at ffffffffa597df53
    ffffc90006fb7c30: 0000000000000020 0000000000000000
    ffffc90006fb7c40: ffffc90006fb7d40 ffff88812cbd3000
    ffffc90006fb7c50: ffffc90006fb7d30 0000000106fb7de8
    ffffc90006fb7c60: ffffea04a2197008 ffffea0006ed4a48
    ffffc90006fb7c70: 0000000000000000 0000000000000000
    ffffc90006fb7c80: 0000000000000000 0000000000000000
    ffffc90006fb7c90: 0000000000000000 0000000000000000
    ffffc90006fb7ca0: 0000000000000000 0000000003e3e937
    ffffc90006fb7cb0: 0000000000000000 0000000000000000
    ffffc90006fb7cc0: 8d7c0b56b7874b00 ffff88812cbd3000

About the Fixes:
Why did it take eight years to be discovered?

The problem requires the following conditions to occur:
1. The device memory should be large enough.
2. Pages in the LRU(active_anon) list are mostly from the ZONE_NORMAL area.
3. The memory in ZONE_DMA32 needs to reach the watermark.

If the memory is not large enough, or if the usage design of ZONE_DMA32
area memory is reasonable, this problem is difficult to detect.

notes:
The problem is most likely to occur in ZONE_DMA32 and ZONE_NORMAL,
but other suitable scenarios may also trigger the problem.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: b2e1875 ("mm, vmscan: begin reclaiming pages on a per-node basis")
Signed-off-by: liuye <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 10, 2025
When COWing a relocation tree path, at relocation.c:replace_path(), we
can trigger a lockdep splat while we are in the btrfs_search_slot() call
against the relocation root. This happens in that callchain at
ctree.c:read_block_for_search() when we happen to find a child extent
buffer already loaded through the fs tree with a lockdep class set to
the fs tree. So when we attempt to lock that extent buffer through a
relocation tree we have to reset the lockdep class to the class for a
relocation tree, since a relocation tree has extent buffers that used
to belong to a fs tree and may currently be already loaded (we swap
extent buffers between the two trees at the end of replace_path()).

However we are missing calls to btrfs_maybe_reset_lockdep_class() to reset
the lockdep class at ctree.c:read_block_for_search() before we read lock
an extent buffer, just like we did for btrfs_search_slot() in commit
b40130b ("btrfs: fix lockdep splat with reloc root extent buffers").

So add the missing btrfs_maybe_reset_lockdep_class() calls before the
attempts to read lock an extent buffer at ctree.c:read_block_for_search().

The lockdep splat was reported by syzbot and it looks like this:

   ======================================================
   WARNING: possible circular locking dependency detected
   6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Not tainted
   ------------------------------------------------------
   syz.0.0/5335 is trying to acquire lock:
   ffff8880545dbc38 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146

   but task is already holding lock:
   ffff8880545dba58 (btrfs-treloc-02/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #2 (btrfs-treloc-02/1){+.+.}-{4:4}:
          reacquire_held_locks+0x3eb/0x690 kernel/locking/lockdep.c:5374
          __lock_release kernel/locking/lockdep.c:5563 [inline]
          lock_release+0x396/0xa30 kernel/locking/lockdep.c:5870
          up_write+0x79/0x590 kernel/locking/rwsem.c:1629
          btrfs_force_cow_block+0x14b3/0x1fd0 fs/btrfs/ctree.c:660
          btrfs_cow_block+0x371/0x830 fs/btrfs/ctree.c:755
          btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2153
          replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224
          merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692
          merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942
          relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754
          btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087
          btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
          __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
          btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
          btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
          vfs_ioctl fs/ioctl.c:51 [inline]
          __do_sys_ioctl fs/ioctl.c:906 [inline]
          __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
          do_syscall_x64 arch/x86/entry/common.c:52 [inline]
          do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
          entry_SYSCALL_64_after_hwframe+0x77/0x7f

   -> #1 (btrfs-tree-01/1){+.+.}-{4:4}:
          lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
          down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
          btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189
          btrfs_init_new_buffer fs/btrfs/extent-tree.c:5052 [inline]
          btrfs_alloc_tree_block+0x41c/0x1440 fs/btrfs/extent-tree.c:5132
          btrfs_force_cow_block+0x526/0x1fd0 fs/btrfs/ctree.c:573
          btrfs_cow_block+0x371/0x830 fs/btrfs/ctree.c:755
          btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2153
          btrfs_insert_empty_items+0x9c/0x1a0 fs/btrfs/ctree.c:4351
          btrfs_insert_empty_item fs/btrfs/ctree.h:688 [inline]
          btrfs_insert_inode_ref+0x2bb/0xf80 fs/btrfs/inode-item.c:330
          btrfs_rename_exchange fs/btrfs/inode.c:7990 [inline]
          btrfs_rename2+0xcb7/0x2b90 fs/btrfs/inode.c:8374
          vfs_rename+0xbdb/0xf00 fs/namei.c:5067
          do_renameat2+0xd94/0x13f0 fs/namei.c:5224
          __do_sys_renameat2 fs/namei.c:5258 [inline]
          __se_sys_renameat2 fs/namei.c:5255 [inline]
          __x64_sys_renameat2+0xce/0xe0 fs/namei.c:5255
          do_syscall_x64 arch/x86/entry/common.c:52 [inline]
          do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
          entry_SYSCALL_64_after_hwframe+0x77/0x7f

   -> #0 (btrfs-tree-01){++++}-{4:4}:
          check_prev_add kernel/locking/lockdep.c:3161 [inline]
          check_prevs_add kernel/locking/lockdep.c:3280 [inline]
          validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
          __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
          lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
          down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
          btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
          btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
          read_block_for_search+0x718/0xbb0 fs/btrfs/ctree.c:1610
          btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2237
          replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224
          merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692
          merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942
          relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754
          btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087
          btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
          __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
          btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
          btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
          vfs_ioctl fs/ioctl.c:51 [inline]
          __do_sys_ioctl fs/ioctl.c:906 [inline]
          __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
          do_syscall_x64 arch/x86/entry/common.c:52 [inline]
          do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
          entry_SYSCALL_64_after_hwframe+0x77/0x7f

   other info that might help us debug this:

   Chain exists of:
     btrfs-tree-01 --> btrfs-tree-01/1 --> btrfs-treloc-02/1

    Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(btrfs-treloc-02/1);
                                  lock(btrfs-tree-01/1);
                                  lock(btrfs-treloc-02/1);
     rlock(btrfs-tree-01);

    *** DEADLOCK ***

   8 locks held by syz.0.0/5335:
    #0: ffff88801e3ae420 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x5e/0x200 fs/namespace.c:559
    #1: ffff888052c760d0 (&fs_info->reclaim_bgs_lock){+.+.}-{4:4}, at: __btrfs_balance+0x4c2/0x26b0 fs/btrfs/volumes.c:4183
    #2: ffff888052c74850 (&fs_info->cleaner_mutex){+.+.}-{4:4}, at: btrfs_relocate_block_group+0x775/0xd90 fs/btrfs/relocation.c:4086
    #3: ffff88801e3ae610 (sb_internal#2){.+.+}-{0:0}, at: merge_reloc_root+0xf11/0x1ad0 fs/btrfs/relocation.c:1659
    #4: ffff888052c76470 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288
    #5: ffff888052c76498 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288
    #6: ffff8880545db878 (btrfs-tree-01/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189
    #7: ffff8880545dba58 (btrfs-treloc-02/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189

   stack backtrace:
   CPU: 0 UID: 0 PID: 5335 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0
   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
   Call Trace:
    <TASK>
    __dump_stack lib/dump_stack.c:94 [inline]
    dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
    print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
    check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
    check_prev_add kernel/locking/lockdep.c:3161 [inline]
    check_prevs_add kernel/locking/lockdep.c:3280 [inline]
    validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
    __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
    lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
    down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
    btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
    btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
    read_block_for_search+0x718/0xbb0 fs/btrfs/ctree.c:1610
    btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2237
    replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224
    merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692
    merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942
    relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754
    btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087
    btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
    __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
    btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
    btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
    vfs_ioctl fs/ioctl.c:51 [inline]
    __do_sys_ioctl fs/ioctl.c:906 [inline]
    __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
    do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   RIP: 0033:0x7f1ac6985d29
   Code: ff ff c3 (...)
   RSP: 002b:00007f1ac63fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
   RAX: ffffffffffffffda RBX: 00007f1ac6b76160 RCX: 00007f1ac6985d29
   RDX: 0000000020000180 RSI: 00000000c4009420 RDI: 0000000000000007
   RBP: 00007f1ac6a01b08 R08: 0000000000000000 R09: 0000000000000000
   R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
   R13: 0000000000000001 R14: 00007f1ac6b76160 R15: 00007fffda145a88
    </TASK>

Reported-by: [email protected]
Link: https://lore.kernel.org/linux-btrfs/[email protected]/
Fixes: 9978599 ("btrfs: reduce lock contention when eb cache miss for btree search")
Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 10, 2025
[ Upstream commit c7b87ce ]

libtraceevent parses and returns an array of argument fields, sometimes
larger than RAW_SYSCALL_ARGS_NUM (6) because it includes "__syscall_nr",
idx will traverse to index 6 (7th element) whereas sc->fmt->arg holds 6
elements max, creating an out-of-bounds access. This runtime error is
found by UBsan. The error message:

  $ sudo UBSAN_OPTIONS=print_stacktrace=1 ./perf trace -a --max-events=1
  builtin-trace.c:1966:35: runtime error: index 6 out of bounds for type 'syscall_arg_fmt [6]'
    #0 0x5c04956be5fe in syscall__alloc_arg_fmts /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:1966
    #1 0x5c04956c0510 in trace__read_syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2110
    #2 0x5c04956c372b in trace__syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2436
    #3 0x5c04956d2f39 in trace__init_syscalls_bpf_prog_array_maps /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:3897
    #4 0x5c04956d6d25 in trace__run /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:4335
    #5 0x5c04956e112e in cmd_trace /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:5502
    #6 0x5c04956eda7d in run_builtin /home/howard/hw/linux-perf/tools/perf/perf.c:351
    #7 0x5c04956ee0a8 in handle_internal_command /home/howard/hw/linux-perf/tools/perf/perf.c:404
    #8 0x5c04956ee37f in run_argv /home/howard/hw/linux-perf/tools/perf/perf.c:448
    #9 0x5c04956ee8e9 in main /home/howard/hw/linux-perf/tools/perf/perf.c:556
    #10 0x79eb3622a3b7 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #11 0x79eb3622a47a in __libc_start_main_impl ../csu/libc-start.c:360
    #12 0x5c04955422d4 in _start (/home/howard/hw/linux-perf/tools/perf/perf+0x4e02d4) (BuildId: 5b6cab2d59e96a4341741765ad6914a4d784dbc6)

     0.000 ( 0.014 ms): Chrome_ChildIO/117244 write(fd: 238, buf: !, count: 1)                                      = 1

Fixes: 5e58fcf ("perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint")
Signed-off-by: Howard Chu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 10, 2025
[ Upstream commit c7b87ce ]

libtraceevent parses and returns an array of argument fields, sometimes
larger than RAW_SYSCALL_ARGS_NUM (6) because it includes "__syscall_nr",
idx will traverse to index 6 (7th element) whereas sc->fmt->arg holds 6
elements max, creating an out-of-bounds access. This runtime error is
found by UBsan. The error message:

  $ sudo UBSAN_OPTIONS=print_stacktrace=1 ./perf trace -a --max-events=1
  builtin-trace.c:1966:35: runtime error: index 6 out of bounds for type 'syscall_arg_fmt [6]'
    #0 0x5c04956be5fe in syscall__alloc_arg_fmts /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:1966
    #1 0x5c04956c0510 in trace__read_syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2110
    #2 0x5c04956c372b in trace__syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2436
    #3 0x5c04956d2f39 in trace__init_syscalls_bpf_prog_array_maps /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:3897
    #4 0x5c04956d6d25 in trace__run /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:4335
    #5 0x5c04956e112e in cmd_trace /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:5502
    #6 0x5c04956eda7d in run_builtin /home/howard/hw/linux-perf/tools/perf/perf.c:351
    #7 0x5c04956ee0a8 in handle_internal_command /home/howard/hw/linux-perf/tools/perf/perf.c:404
    #8 0x5c04956ee37f in run_argv /home/howard/hw/linux-perf/tools/perf/perf.c:448
    #9 0x5c04956ee8e9 in main /home/howard/hw/linux-perf/tools/perf/perf.c:556
    #10 0x79eb3622a3b7 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #11 0x79eb3622a47a in __libc_start_main_impl ../csu/libc-start.c:360
    #12 0x5c04955422d4 in _start (/home/howard/hw/linux-perf/tools/perf/perf+0x4e02d4) (BuildId: 5b6cab2d59e96a4341741765ad6914a4d784dbc6)

     0.000 ( 0.014 ms): Chrome_ChildIO/117244 write(fd: 238, buf: !, count: 1)                                      = 1

Fixes: 5e58fcf ("perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint")
Signed-off-by: Howard Chu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 13, 2025
[ Upstream commit c7b87ce ]

libtraceevent parses and returns an array of argument fields, sometimes
larger than RAW_SYSCALL_ARGS_NUM (6) because it includes "__syscall_nr",
idx will traverse to index 6 (7th element) whereas sc->fmt->arg holds 6
elements max, creating an out-of-bounds access. This runtime error is
found by UBsan. The error message:

  $ sudo UBSAN_OPTIONS=print_stacktrace=1 ./perf trace -a --max-events=1
  builtin-trace.c:1966:35: runtime error: index 6 out of bounds for type 'syscall_arg_fmt [6]'
    #0 0x5c04956be5fe in syscall__alloc_arg_fmts /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:1966
    #1 0x5c04956c0510 in trace__read_syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2110
    #2 0x5c04956c372b in trace__syscall_info /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:2436
    #3 0x5c04956d2f39 in trace__init_syscalls_bpf_prog_array_maps /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:3897
    #4 0x5c04956d6d25 in trace__run /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:4335
    #5 0x5c04956e112e in cmd_trace /home/howard/hw/linux-perf/tools/perf/builtin-trace.c:5502
    #6 0x5c04956eda7d in run_builtin /home/howard/hw/linux-perf/tools/perf/perf.c:351
    #7 0x5c04956ee0a8 in handle_internal_command /home/howard/hw/linux-perf/tools/perf/perf.c:404
    #8 0x5c04956ee37f in run_argv /home/howard/hw/linux-perf/tools/perf/perf.c:448
    #9 0x5c04956ee8e9 in main /home/howard/hw/linux-perf/tools/perf/perf.c:556
    #10 0x79eb3622a3b7 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #11 0x79eb3622a47a in __libc_start_main_impl ../csu/libc-start.c:360
    #12 0x5c04955422d4 in _start (/home/howard/hw/linux-perf/tools/perf/perf+0x4e02d4) (BuildId: 5b6cab2d59e96a4341741765ad6914a4d784dbc6)

     0.000 ( 0.014 ms): Chrome_ChildIO/117244 write(fd: 238, buf: !, count: 1)                                      = 1

Fixes: 5e58fcf ("perf trace: Allow allocating sc->arg_fmt even without the syscall tracepoint")
Signed-off-by: Howard Chu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 17, 2025
We have several places across the kernel where we want to access another
task's syscall arguments, such as ptrace(2), seccomp(2), etc., by making
a call to syscall_get_arguments().

This works for register arguments right away by accessing the task's
`regs' member of `struct pt_regs', however for stack arguments seen with
32-bit/o32 kernels things are more complicated.  Technically they ought
to be obtained from the user stack with calls to an access_remote_vm(),
but we have an easier way available already.

So as to be able to access syscall stack arguments as regular function
arguments following the MIPS calling convention we copy them over from
the user stack to the kernel stack in arch/mips/kernel/scall32-o32.S, in
handle_sys(), to the current stack frame's outgoing argument space at
the top of the stack, which is where the handler called expects to see
its incoming arguments.  This area is also pointed at by the `pt_regs'
pointer obtained by task_pt_regs().

Make the o32 stack argument space a proper member of `struct pt_regs'
then, by renaming the existing member from `pad0' to `args' and using
generated offsets to access the space.  No functional change though.

With the change in place the o32 kernel stack frame layout at the entry
to a syscall handler invoked by handle_sys() is therefore as follows:

$sp + 68 -> |         ...         | <- pt_regs.regs[9]
            +---------------------+
$sp + 64 -> |         $t0         | <- pt_regs.regs[8]
            +---------------------+
$sp + 60 -> |   $a3/argument #4   | <- pt_regs.regs[7]
            +---------------------+
$sp + 56 -> |   $a2/argument #3   | <- pt_regs.regs[6]
            +---------------------+
$sp + 52 -> |   $a1/argument #2   | <- pt_regs.regs[5]
            +---------------------+
$sp + 48 -> |   $a0/argument #1   | <- pt_regs.regs[4]
            +---------------------+
$sp + 44 -> |         $v1         | <- pt_regs.regs[3]
            +---------------------+
$sp + 40 -> |         $v0         | <- pt_regs.regs[2]
            +---------------------+
$sp + 36 -> |         $at         | <- pt_regs.regs[1]
            +---------------------+
$sp + 32 -> |        $zero        | <- pt_regs.regs[0]
            +---------------------+
$sp + 28 -> |  stack argument #8  | <- pt_regs.args[7]
            +---------------------+
$sp + 24 -> |  stack argument #7  | <- pt_regs.args[6]
            +---------------------+
$sp + 20 -> |  stack argument #6  | <- pt_regs.args[5]
            +---------------------+
$sp + 16 -> |  stack argument #5  | <- pt_regs.args[4]
            +---------------------+
$sp + 12 -> | psABI space for $a3 | <- pt_regs.args[3]
            +---------------------+
$sp +  8 -> | psABI space for $a2 | <- pt_regs.args[2]
            +---------------------+
$sp +  4 -> | psABI space for $a1 | <- pt_regs.args[1]
            +---------------------+
$sp +  0 -> | psABI space for $a0 | <- pt_regs.args[0]
            +---------------------+

holding user data received and with the first 4 frame slots reserved by
the psABI for the compiler to spill the incoming arguments from $a0-$a3
registers (which it sometimes does according to its needs) and the next
4 frame slots designated by the psABI for any stack function arguments
that follow.  This data is also available for other tasks to peek/poke
at as reqired and where permitted.

Signed-off-by: Maciej W. Rozycki <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 17, 2025
This makes ptrace/get_syscall_info selftest pass on mips o32 and
mips64 o32 by fixing the following two test assertions:

1. get_syscall_info test assertion on mips o32:
  # get_syscall_info.c:218:get_syscall_info:Expected exp_args[5] (3134521044) == info.entry.args[4] (4911432)
  # get_syscall_info.c:219:get_syscall_info:wait #1: entry stop mismatch

2. get_syscall_info test assertion on mips64 o32:
  # get_syscall_info.c:209:get_syscall_info:Expected exp_args[2] (3134324433) == info.entry.args[1] (18446744072548908753)
  # get_syscall_info.c:210:get_syscall_info:wait #1: entry stop mismatch

The first assertion happens due to mips_get_syscall_arg() trying to access
another task's context but failing to do it properly because get_user() it
calls just peeks at the current task's context.  It usually does not crash
because the default user stack always gets assigned the same VMA, but it
is pure luck which mips_get_syscall_arg() wouldn't have if e.g. the stack
was switched (via setcontext(3) or however) or a non-default process's
thread peeked at, and in any case irrelevant data is obtained just as
observed with the test case.

mips_get_syscall_arg() ought to be using access_remote_vm() instead to
retrieve the other task's stack contents, but given that the data has been
already obtained and saved in `struct pt_regs' it would be an overkill.

The first assertion is fixed for mips o32 by using struct pt_regs.args
instead of get_user() to obtain syscall arguments.  This approach works
due to this piece in arch/mips/kernel/scall32-o32.S:

        /*
         * Ok, copy the args from the luser stack to the kernel stack.
         */

        .set    push
        .set    noreorder
        .set    nomacro

    load_a4: user_lw(t5, 16(t0))		# argument #5 from usp
    load_a5: user_lw(t6, 20(t0))		# argument #6 from usp
    load_a6: user_lw(t7, 24(t0))		# argument #7 from usp
    load_a7: user_lw(t8, 28(t0))		# argument #8 from usp
    loads_done:

        sw	t5, PT_ARG4(sp)		# argument #5 to ksp
        sw	t6, PT_ARG5(sp)		# argument #6 to ksp
        sw	t7, PT_ARG6(sp)		# argument #7 to ksp
        sw	t8, PT_ARG7(sp)		# argument #8 to ksp
        .set	pop

        .section __ex_table,"a"
        PTR_WD	load_a4, bad_stack_a4
        PTR_WD	load_a5, bad_stack_a5
        PTR_WD	load_a6, bad_stack_a6
        PTR_WD	load_a7, bad_stack_a7
        .previous

arch/mips/kernel/scall64-o32.S has analogous code for mips64 o32 that
allows fixing the issue by obtaining syscall arguments from struct
pt_regs.regs[4..11] instead of the erroneous use of get_user().

The second assertion is fixed by truncating 64-bit values to 32-bit
syscall arguments.

Fixes: c0ff3c5 ("MIPS: Enable HAVE_ARCH_TRACEHOOK.")
Signed-off-by: Dmitry V. Levin <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
popcornmix pushed a commit that referenced this issue Feb 17, 2025
[ Upstream commit a216542 ]

When COWing a relocation tree path, at relocation.c:replace_path(), we
can trigger a lockdep splat while we are in the btrfs_search_slot() call
against the relocation root. This happens in that callchain at
ctree.c:read_block_for_search() when we happen to find a child extent
buffer already loaded through the fs tree with a lockdep class set to
the fs tree. So when we attempt to lock that extent buffer through a
relocation tree we have to reset the lockdep class to the class for a
relocation tree, since a relocation tree has extent buffers that used
to belong to a fs tree and may currently be already loaded (we swap
extent buffers between the two trees at the end of replace_path()).

However we are missing calls to btrfs_maybe_reset_lockdep_class() to reset
the lockdep class at ctree.c:read_block_for_search() before we read lock
an extent buffer, just like we did for btrfs_search_slot() in commit
b40130b ("btrfs: fix lockdep splat with reloc root extent buffers").

So add the missing btrfs_maybe_reset_lockdep_class() calls before the
attempts to read lock an extent buffer at ctree.c:read_block_for_search().

The lockdep splat was reported by syzbot and it looks like this:

   ======================================================
   WARNING: possible circular locking dependency detected
   6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Not tainted
   ------------------------------------------------------
   syz.0.0/5335 is trying to acquire lock:
   ffff8880545dbc38 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146

   but task is already holding lock:
   ffff8880545dba58 (btrfs-treloc-02/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #2 (btrfs-treloc-02/1){+.+.}-{4:4}:
          reacquire_held_locks+0x3eb/0x690 kernel/locking/lockdep.c:5374
          __lock_release kernel/locking/lockdep.c:5563 [inline]
          lock_release+0x396/0xa30 kernel/locking/lockdep.c:5870
          up_write+0x79/0x590 kernel/locking/rwsem.c:1629
          btrfs_force_cow_block+0x14b3/0x1fd0 fs/btrfs/ctree.c:660
          btrfs_cow_block+0x371/0x830 fs/btrfs/ctree.c:755
          btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2153
          replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224
          merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692
          merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942
          relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754
          btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087
          btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
          __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
          btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
          btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
          vfs_ioctl fs/ioctl.c:51 [inline]
          __do_sys_ioctl fs/ioctl.c:906 [inline]
          __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
          do_syscall_x64 arch/x86/entry/common.c:52 [inline]
          do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
          entry_SYSCALL_64_after_hwframe+0x77/0x7f

   -> #1 (btrfs-tree-01/1){+.+.}-{4:4}:
          lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
          down_write_nested+0xa2/0x220 kernel/locking/rwsem.c:1693
          btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189
          btrfs_init_new_buffer fs/btrfs/extent-tree.c:5052 [inline]
          btrfs_alloc_tree_block+0x41c/0x1440 fs/btrfs/extent-tree.c:5132
          btrfs_force_cow_block+0x526/0x1fd0 fs/btrfs/ctree.c:573
          btrfs_cow_block+0x371/0x830 fs/btrfs/ctree.c:755
          btrfs_search_slot+0xc01/0x3180 fs/btrfs/ctree.c:2153
          btrfs_insert_empty_items+0x9c/0x1a0 fs/btrfs/ctree.c:4351
          btrfs_insert_empty_item fs/btrfs/ctree.h:688 [inline]
          btrfs_insert_inode_ref+0x2bb/0xf80 fs/btrfs/inode-item.c:330
          btrfs_rename_exchange fs/btrfs/inode.c:7990 [inline]
          btrfs_rename2+0xcb7/0x2b90 fs/btrfs/inode.c:8374
          vfs_rename+0xbdb/0xf00 fs/namei.c:5067
          do_renameat2+0xd94/0x13f0 fs/namei.c:5224
          __do_sys_renameat2 fs/namei.c:5258 [inline]
          __se_sys_renameat2 fs/namei.c:5255 [inline]
          __x64_sys_renameat2+0xce/0xe0 fs/namei.c:5255
          do_syscall_x64 arch/x86/entry/common.c:52 [inline]
          do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
          entry_SYSCALL_64_after_hwframe+0x77/0x7f

   -> #0 (btrfs-tree-01){++++}-{4:4}:
          check_prev_add kernel/locking/lockdep.c:3161 [inline]
          check_prevs_add kernel/locking/lockdep.c:3280 [inline]
          validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
          __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
          lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
          down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
          btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
          btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
          read_block_for_search+0x718/0xbb0 fs/btrfs/ctree.c:1610
          btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2237
          replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224
          merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692
          merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942
          relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754
          btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087
          btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
          __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
          btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
          btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
          vfs_ioctl fs/ioctl.c:51 [inline]
          __do_sys_ioctl fs/ioctl.c:906 [inline]
          __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
          do_syscall_x64 arch/x86/entry/common.c:52 [inline]
          do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
          entry_SYSCALL_64_after_hwframe+0x77/0x7f

   other info that might help us debug this:

   Chain exists of:
     btrfs-tree-01 --> btrfs-tree-01/1 --> btrfs-treloc-02/1

    Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(btrfs-treloc-02/1);
                                  lock(btrfs-tree-01/1);
                                  lock(btrfs-treloc-02/1);
     rlock(btrfs-tree-01);

    *** DEADLOCK ***

   8 locks held by syz.0.0/5335:
    #0: ffff88801e3ae420 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write_file+0x5e/0x200 fs/namespace.c:559
    #1: ffff888052c760d0 (&fs_info->reclaim_bgs_lock){+.+.}-{4:4}, at: __btrfs_balance+0x4c2/0x26b0 fs/btrfs/volumes.c:4183
    #2: ffff888052c74850 (&fs_info->cleaner_mutex){+.+.}-{4:4}, at: btrfs_relocate_block_group+0x775/0xd90 fs/btrfs/relocation.c:4086
    #3: ffff88801e3ae610 (sb_internal#2){.+.+}-{0:0}, at: merge_reloc_root+0xf11/0x1ad0 fs/btrfs/relocation.c:1659
    #4: ffff888052c76470 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288
    #5: ffff888052c76498 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288
    #6: ffff8880545db878 (btrfs-tree-01/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189
    #7: ffff8880545dba58 (btrfs-treloc-02/1){+.+.}-{4:4}, at: btrfs_tree_lock_nested+0x2f/0x250 fs/btrfs/locking.c:189

   stack backtrace:
   CPU: 0 UID: 0 PID: 5335 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0
   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
   Call Trace:
    <TASK>
    __dump_stack lib/dump_stack.c:94 [inline]
    dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
    print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
    check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
    check_prev_add kernel/locking/lockdep.c:3161 [inline]
    check_prevs_add kernel/locking/lockdep.c:3280 [inline]
    validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
    __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
    lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
    down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
    btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
    btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
    read_block_for_search+0x718/0xbb0 fs/btrfs/ctree.c:1610
    btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2237
    replace_path+0x1243/0x2740 fs/btrfs/relocation.c:1224
    merge_reloc_root+0xc46/0x1ad0 fs/btrfs/relocation.c:1692
    merge_reloc_roots+0x3b3/0x980 fs/btrfs/relocation.c:1942
    relocate_block_group+0xb0a/0xd40 fs/btrfs/relocation.c:3754
    btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4087
    btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3494
    __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4278
    btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4655
    btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3670
    vfs_ioctl fs/ioctl.c:51 [inline]
    __do_sys_ioctl fs/ioctl.c:906 [inline]
    __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
    do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   RIP: 0033:0x7f1ac6985d29
   Code: ff ff c3 (...)
   RSP: 002b:00007f1ac63fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
   RAX: ffffffffffffffda RBX: 00007f1ac6b76160 RCX: 00007f1ac6985d29
   RDX: 0000000020000180 RSI: 00000000c4009420 RDI: 0000000000000007
   RBP: 00007f1ac6a01b08 R08: 0000000000000000 R09: 0000000000000000
   R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
   R13: 0000000000000001 R14: 00007f1ac6b76160 R15: 00007fffda145a88
    </TASK>

Reported-by: [email protected]
Link: https://lore.kernel.org/linux-btrfs/[email protected]/
Fixes: 9978599 ("btrfs: reduce lock contention when eb cache miss for btree search")
Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 10, 2025
[ Upstream commit 888751e ]

perf test 11 hwmon fails on s390 with this error

 # ./perf test -Fv 11
 --- start ---
 ---- end ----
 11.1: Basic parsing test             : Ok
 --- start ---
 Testing 'temp_test_hwmon_event1'
 Using CPUID IBM,3931,704,A01,3.7,002f
 temp_test_hwmon_event1 -> hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/
 FAILED tests/hwmon_pmu.c:189 Unexpected config for
    'temp_test_hwmon_event1', 292470092988416 != 655361
 ---- end ----
 11.2: Parsing without PMU name       : FAILED!
 --- start ---
 Testing 'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/'
 FAILED tests/hwmon_pmu.c:189 Unexpected config for
    'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/',
    292470092988416 != 655361
 ---- end ----
 11.3: Parsing with PMU name          : FAILED!
 #

The root cause is in member test_event::config which is initialized
to 0xA0001 or 655361. During event parsing a long list event parsing
functions are called and end up with this gdb call stack:

 #0  hwmon_pmu__config_term (hwm=0x168dfd0, attr=0x3ffffff5ee8,
	term=0x168db60, err=0x3ffffff81c8) at util/hwmon_pmu.c:623
 #1  hwmon_pmu__config_terms (pmu=0x168dfd0, attr=0x3ffffff5ee8,
	terms=0x3ffffff5ea8, err=0x3ffffff81c8) at util/hwmon_pmu.c:662
 #2  0x00000000012f870c in perf_pmu__config_terms (pmu=0x168dfd0,
	attr=0x3ffffff5ee8, terms=0x3ffffff5ea8, zero=false,
	apply_hardcoded=false, err=0x3ffffff81c8) at util/pmu.c:1519
 #3  0x00000000012f88a4 in perf_pmu__config (pmu=0x168dfd0, attr=0x3ffffff5ee8,
	head_terms=0x3ffffff5ea8, apply_hardcoded=false, err=0x3ffffff81c8)
	at util/pmu.c:1545
 #4  0x00000000012680c4 in parse_events_add_pmu (parse_state=0x3ffffff7fb8,
	list=0x168dc00, pmu=0x168dfd0, const_parsed_terms=0x3ffffff6090,
	auto_merge_stats=true, alternate_hw_config=10)
	at util/parse-events.c:1508
 #5  0x00000000012684c6 in parse_events_multi_pmu_add (parse_state=0x3ffffff7fb8,
	event_name=0x168ec10 "temp_test_hwmon_event1", hw_config=10,
	const_parsed_terms=0x0, listp=0x3ffffff6230, loc_=0x3ffffff70e0)
	at util/parse-events.c:1592
 #6  0x00000000012f0e4e in parse_events_parse (_parse_state=0x3ffffff7fb8,
	scanner=0x16878c0) at util/parse-events.y:293
 #7  0x00000000012695a0 in parse_events__scanner (str=0x3ffffff81d8
	"temp_test_hwmon_event1", input=0x0, parse_state=0x3ffffff7fb8)
	at util/parse-events.c:1867
 #8  0x000000000126a1e8 in __parse_events (evlist=0x168b580,
	str=0x3ffffff81d8 "temp_test_hwmon_event1", pmu_filter=0x0,
	err=0x3ffffff81c8, fake_pmu=false, warn_if_reordered=true,
	fake_tp=false) at util/parse-events.c:2136
 #9  0x00000000011e36aa in parse_events (evlist=0x168b580,
	str=0x3ffffff81d8 "temp_test_hwmon_event1", err=0x3ffffff81c8)
	at /root/linux/tools/perf/util/parse-events.h:41
 #10 0x00000000011e3e64 in do_test (i=0, with_pmu=false, with_alias=false)
	at tests/hwmon_pmu.c:164
 #11 0x00000000011e422c in test__hwmon_pmu (with_pmu=false)
	at tests/hwmon_pmu.c:219
 #12 0x00000000011e431c in test__hwmon_pmu_without_pmu (test=0x1610368
	<suite.hwmon_pmu>, subtest=1) at tests/hwmon_pmu.c:23

where the attr::config is set to value 292470092988416 or 0x10a0000000000
in line 625 of file ./util/hwmon_pmu.c:

   attr->config = key.type_and_num;

However member key::type_and_num is defined as union and bit field:

   union hwmon_pmu_event_key {
        long type_and_num;
        struct {
                int num :16;
                enum hwmon_type type :8;
        };
   };

s390 is big endian and Intel is little endian architecture.
The events for the hwmon dummy pmu have num = 1 or num = 2 and
type is set to HWMON_TYPE_TEMP (which is 10).
On s390 this assignes member key::type_and_num the value of
0x10a0000000000 (which is 292470092988416) as shown in above
trace output.

Fix this and export the structure/union hwmon_pmu_event_key
so the test shares the same implementation as the event parsing
functions for union and bit fields. This should avoid
endianess issues on all platforms.

Output after:
 # ./perf test -F 11
 11.1: Basic parsing test         : Ok
 11.2: Parsing without PMU name   : Ok
 11.3: Parsing with PMU name      : Ok
 #

Fixes: 531ee0f ("perf test: Add hwmon "PMU" test")
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 10, 2025
[ Upstream commit 6260406 ]

In ThinPro, we use the convention <upstream_ver>+hp<patchlevel> for
the kernel package. This does not have a dash in the name or version.
This is built by editing ".version" before a build, and setting
EXTRAVERSION="+hp" and KDEB_PKGVERSION make variables:

    echo 68 > .version
    make -j<n> EXTRAVERSION="+hp" bindeb-pkg KDEB_PKGVERSION=6.12.2+hp69

    .deb name: linux-image-6.12.2+hp_6.12.2+hp69_amd64.deb

Since commit 7d4f07d ("kbuild: deb-pkg: squash
scripts/package/deb-build-option to debian/rules"), this no longer
works. The deb build logic changed, even though, the commit message
implies that the logic should be unmodified.

Before, KBUILD_BUILD_VERSION was not set if the KDEB_PKGVERSION did
not contain a dash. After the change KBUILD_BUILD_VERSION is always
set to KDEB_PKGVERSION. Since this determines UTS_VERSION, the uname
output to look off:

    (now)      uname -a: version 6.12.2+hp ... #6.12.2+hp69
    (expected) uname -a: version 6.12.2+hp ... #69

Update the debian/rules logic to restore the original behavior.

Fixes: 7d4f07d ("kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules")
Signed-off-by: Alexandru Gagniuc <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
[ Upstream commit 888751e ]

perf test 11 hwmon fails on s390 with this error

 # ./perf test -Fv 11
 --- start ---
 ---- end ----
 11.1: Basic parsing test             : Ok
 --- start ---
 Testing 'temp_test_hwmon_event1'
 Using CPUID IBM,3931,704,A01,3.7,002f
 temp_test_hwmon_event1 -> hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/
 FAILED tests/hwmon_pmu.c:189 Unexpected config for
    'temp_test_hwmon_event1', 292470092988416 != 655361
 ---- end ----
 11.2: Parsing without PMU name       : FAILED!
 --- start ---
 Testing 'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/'
 FAILED tests/hwmon_pmu.c:189 Unexpected config for
    'hwmon_a_test_hwmon_pmu/temp_test_hwmon_event1/',
    292470092988416 != 655361
 ---- end ----
 11.3: Parsing with PMU name          : FAILED!
 #

The root cause is in member test_event::config which is initialized
to 0xA0001 or 655361. During event parsing a long list event parsing
functions are called and end up with this gdb call stack:

 #0  hwmon_pmu__config_term (hwm=0x168dfd0, attr=0x3ffffff5ee8,
	term=0x168db60, err=0x3ffffff81c8) at util/hwmon_pmu.c:623
 #1  hwmon_pmu__config_terms (pmu=0x168dfd0, attr=0x3ffffff5ee8,
	terms=0x3ffffff5ea8, err=0x3ffffff81c8) at util/hwmon_pmu.c:662
 #2  0x00000000012f870c in perf_pmu__config_terms (pmu=0x168dfd0,
	attr=0x3ffffff5ee8, terms=0x3ffffff5ea8, zero=false,
	apply_hardcoded=false, err=0x3ffffff81c8) at util/pmu.c:1519
 #3  0x00000000012f88a4 in perf_pmu__config (pmu=0x168dfd0, attr=0x3ffffff5ee8,
	head_terms=0x3ffffff5ea8, apply_hardcoded=false, err=0x3ffffff81c8)
	at util/pmu.c:1545
 #4  0x00000000012680c4 in parse_events_add_pmu (parse_state=0x3ffffff7fb8,
	list=0x168dc00, pmu=0x168dfd0, const_parsed_terms=0x3ffffff6090,
	auto_merge_stats=true, alternate_hw_config=10)
	at util/parse-events.c:1508
 #5  0x00000000012684c6 in parse_events_multi_pmu_add (parse_state=0x3ffffff7fb8,
	event_name=0x168ec10 "temp_test_hwmon_event1", hw_config=10,
	const_parsed_terms=0x0, listp=0x3ffffff6230, loc_=0x3ffffff70e0)
	at util/parse-events.c:1592
 #6  0x00000000012f0e4e in parse_events_parse (_parse_state=0x3ffffff7fb8,
	scanner=0x16878c0) at util/parse-events.y:293
 #7  0x00000000012695a0 in parse_events__scanner (str=0x3ffffff81d8
	"temp_test_hwmon_event1", input=0x0, parse_state=0x3ffffff7fb8)
	at util/parse-events.c:1867
 #8  0x000000000126a1e8 in __parse_events (evlist=0x168b580,
	str=0x3ffffff81d8 "temp_test_hwmon_event1", pmu_filter=0x0,
	err=0x3ffffff81c8, fake_pmu=false, warn_if_reordered=true,
	fake_tp=false) at util/parse-events.c:2136
 #9  0x00000000011e36aa in parse_events (evlist=0x168b580,
	str=0x3ffffff81d8 "temp_test_hwmon_event1", err=0x3ffffff81c8)
	at /root/linux/tools/perf/util/parse-events.h:41
 #10 0x00000000011e3e64 in do_test (i=0, with_pmu=false, with_alias=false)
	at tests/hwmon_pmu.c:164
 #11 0x00000000011e422c in test__hwmon_pmu (with_pmu=false)
	at tests/hwmon_pmu.c:219
 #12 0x00000000011e431c in test__hwmon_pmu_without_pmu (test=0x1610368
	<suite.hwmon_pmu>, subtest=1) at tests/hwmon_pmu.c:23

where the attr::config is set to value 292470092988416 or 0x10a0000000000
in line 625 of file ./util/hwmon_pmu.c:

   attr->config = key.type_and_num;

However member key::type_and_num is defined as union and bit field:

   union hwmon_pmu_event_key {
        long type_and_num;
        struct {
                int num :16;
                enum hwmon_type type :8;
        };
   };

s390 is big endian and Intel is little endian architecture.
The events for the hwmon dummy pmu have num = 1 or num = 2 and
type is set to HWMON_TYPE_TEMP (which is 10).
On s390 this assignes member key::type_and_num the value of
0x10a0000000000 (which is 292470092988416) as shown in above
trace output.

Fix this and export the structure/union hwmon_pmu_event_key
so the test shares the same implementation as the event parsing
functions for union and bit fields. This should avoid
endianess issues on all platforms.

Output after:
 # ./perf test -F 11
 11.1: Basic parsing test         : Ok
 11.2: Parsing without PMU name   : Ok
 11.3: Parsing with PMU name      : Ok
 #

Fixes: 531ee0f ("perf test: Add hwmon "PMU" test")
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 14, 2025
[ Upstream commit 6260406 ]

In ThinPro, we use the convention <upstream_ver>+hp<patchlevel> for
the kernel package. This does not have a dash in the name or version.
This is built by editing ".version" before a build, and setting
EXTRAVERSION="+hp" and KDEB_PKGVERSION make variables:

    echo 68 > .version
    make -j<n> EXTRAVERSION="+hp" bindeb-pkg KDEB_PKGVERSION=6.12.2+hp69

    .deb name: linux-image-6.12.2+hp_6.12.2+hp69_amd64.deb

Since commit 7d4f07d ("kbuild: deb-pkg: squash
scripts/package/deb-build-option to debian/rules"), this no longer
works. The deb build logic changed, even though, the commit message
implies that the logic should be unmodified.

Before, KBUILD_BUILD_VERSION was not set if the KDEB_PKGVERSION did
not contain a dash. After the change KBUILD_BUILD_VERSION is always
set to KDEB_PKGVERSION. Since this determines UTS_VERSION, the uname
output to look off:

    (now)      uname -a: version 6.12.2+hp ... #6.12.2+hp69
    (expected) uname -a: version 6.12.2+hp ... #69

Update the debian/rules logic to restore the original behavior.

Fixes: 7d4f07d ("kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules")
Signed-off-by: Alexandru Gagniuc <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
syzkaller triggered an oversized kvmalloc() warning.
Silence it by adding __GFP_NOWARN.

syzkaller log:
 WARNING: CPU: 7 PID: 518 at mm/util.c:665 __kvmalloc_node_noprof+0x175/0x180
 CPU: 7 UID: 0 PID: 518 Comm: c_repro Not tainted 6.11.0-rc6+ #6
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 RIP: 0010:__kvmalloc_node_noprof+0x175/0x180
 RSP: 0018:ffffc90001e67c10 EFLAGS: 00010246
 RAX: 0000000000000100 RBX: 0000000000000400 RCX: ffffffff8149d46b
 RDX: 0000000000000000 RSI: ffff8881030fae80 RDI: 0000000000000002
 RBP: 000000712c800000 R08: 0000000000000100 R09: 0000000000000000
 R10: ffffc90001e67c10 R11: 0030ae0601000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000000
 FS:  00007fde79159740(0000) GS:ffff88813bdc0000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000020000180 CR3: 0000000105eb4005 CR4: 00000000003706b0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  <TASK>
  ib_umem_odp_get+0x1f6/0x390
  mlx5_ib_reg_user_mr+0x1e8/0x450
  ib_uverbs_reg_mr+0x28b/0x440
  ib_uverbs_write+0x7d3/0xa30
  vfs_write+0x1ac/0x6c0
  ksys_write+0x134/0x170
  ? __sanitizer_cov_trace_pc+0x1c/0x50
  do_syscall_64+0x50/0x110
  entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fixes: 3782495 ("RDMA/odp: Use kvcalloc for the dma_list and page_list")
Signed-off-by: Shay Drory <[email protected]>
Link: https://patch.msgid.link/c6cb92379de668be94894f49c2cfa40e73f94d56.1742388096.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
commit 93ae6e6 upstream.

We have recently seen report of lockdep circular lock dependency warnings
on platforms like Skylake and Kabylake:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc6-CI_DRM_16276-gca2c04fe76e8+ #1 Not tainted
 ------------------------------------------------------
 swapper/0/1 is trying to acquire lock:
 ffffffff8360ee48 (iommu_probe_device_lock){+.+.}-{3:3},
   at: iommu_probe_device+0x1d/0x70

 but task is already holding lock:
 ffff888102c7efa8 (&device->physical_node_lock){+.+.}-{3:3},
   at: intel_iommu_init+0xe75/0x11f0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&device->physical_node_lock){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        intel_iommu_init+0xe75/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #5 (dmar_global_lock){++++}-{3:3}:
        down_read+0x43/0x1d0
        enable_drhd_fault_handling+0x21/0x110
        cpuhp_invoke_callback+0x4c6/0x870
        cpuhp_issue_call+0xbf/0x1f0
        __cpuhp_setup_state_cpuslocked+0x111/0x320
        __cpuhp_setup_state+0xb0/0x220
        irq_remap_enable_fault_handling+0x3f/0xa0
        apic_intr_mode_init+0x5c/0x110
        x86_late_time_init+0x24/0x40
        start_kernel+0x895/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #4 (cpuhp_state_mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __cpuhp_setup_state_cpuslocked+0x67/0x320
        __cpuhp_setup_state+0xb0/0x220
        page_alloc_init_cpuhp+0x2d/0x60
        mm_core_init+0x18/0x2c0
        start_kernel+0x576/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #3 (cpu_hotplug_lock){++++}-{0:0}:
        __cpuhp_state_add_instance+0x4f/0x220
        iova_domain_init_rcaches+0x214/0x280
        iommu_setup_dma_ops+0x1a4/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&domain->iova_cookie->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_setup_dma_ops+0x16b/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&group->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __iommu_probe_device+0x24c/0x4e0
        probe_iommu_group+0x2b/0x50
        bus_for_each_dev+0x7d/0xe0
        iommu_device_register+0xe1/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 (iommu_probe_device_lock){+.+.}-{3:3}:
        __lock_acquire+0x1637/0x2810
        lock_acquire+0xc9/0x300
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_probe_device+0x1d/0x70
        intel_iommu_init+0xe90/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

 Chain exists of:
   iommu_probe_device_lock --> dmar_global_lock -->
     &device->physical_node_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&device->physical_node_lock);
                                lock(dmar_global_lock);
                                lock(&device->physical_node_lock);
   lock(iommu_probe_device_lock);

  *** DEADLOCK ***

This driver uses a global lock to protect the list of enumerated DMA
remapping units. It is necessary due to the driver's support for dynamic
addition and removal of remapping units at runtime.

Two distinct code paths require iteration over this remapping unit list:

- Device registration and probing: the driver iterates the list to
  register each remapping unit with the upper layer IOMMU framework
  and subsequently probe the devices managed by that unit.
- Global configuration: Upper layer components may also iterate the list
  to apply configuration changes.

The lock acquisition order between these two code paths was reversed. This
caused lockdep warnings, indicating a risk of deadlock. Fix this warning
by releasing the global lock before invoking upper layer interfaces for
device registration.

Fixes: b150654 ("iommu/vt-d: Fix suspicious RCU usage")
Closes: https://lore.kernel.org/linux-iommu/SJ1PR11MB612953431F94F18C954C4A9CB9D32@SJ1PR11MB6129.namprd11.prod.outlook.com/
Tested-by: Chaitanya Kumar Borah <[email protected]>
Cc: [email protected]
Signed-off-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 24, 2025
commit 93ae6e6 upstream.

We have recently seen report of lockdep circular lock dependency warnings
on platforms like Skylake and Kabylake:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc6-CI_DRM_16276-gca2c04fe76e8+ #1 Not tainted
 ------------------------------------------------------
 swapper/0/1 is trying to acquire lock:
 ffffffff8360ee48 (iommu_probe_device_lock){+.+.}-{3:3},
   at: iommu_probe_device+0x1d/0x70

 but task is already holding lock:
 ffff888102c7efa8 (&device->physical_node_lock){+.+.}-{3:3},
   at: intel_iommu_init+0xe75/0x11f0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&device->physical_node_lock){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        intel_iommu_init+0xe75/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #5 (dmar_global_lock){++++}-{3:3}:
        down_read+0x43/0x1d0
        enable_drhd_fault_handling+0x21/0x110
        cpuhp_invoke_callback+0x4c6/0x870
        cpuhp_issue_call+0xbf/0x1f0
        __cpuhp_setup_state_cpuslocked+0x111/0x320
        __cpuhp_setup_state+0xb0/0x220
        irq_remap_enable_fault_handling+0x3f/0xa0
        apic_intr_mode_init+0x5c/0x110
        x86_late_time_init+0x24/0x40
        start_kernel+0x895/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #4 (cpuhp_state_mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __cpuhp_setup_state_cpuslocked+0x67/0x320
        __cpuhp_setup_state+0xb0/0x220
        page_alloc_init_cpuhp+0x2d/0x60
        mm_core_init+0x18/0x2c0
        start_kernel+0x576/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #3 (cpu_hotplug_lock){++++}-{0:0}:
        __cpuhp_state_add_instance+0x4f/0x220
        iova_domain_init_rcaches+0x214/0x280
        iommu_setup_dma_ops+0x1a4/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&domain->iova_cookie->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_setup_dma_ops+0x16b/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&group->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __iommu_probe_device+0x24c/0x4e0
        probe_iommu_group+0x2b/0x50
        bus_for_each_dev+0x7d/0xe0
        iommu_device_register+0xe1/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 (iommu_probe_device_lock){+.+.}-{3:3}:
        __lock_acquire+0x1637/0x2810
        lock_acquire+0xc9/0x300
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_probe_device+0x1d/0x70
        intel_iommu_init+0xe90/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

 Chain exists of:
   iommu_probe_device_lock --> dmar_global_lock -->
     &device->physical_node_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&device->physical_node_lock);
                                lock(dmar_global_lock);
                                lock(&device->physical_node_lock);
   lock(iommu_probe_device_lock);

  *** DEADLOCK ***

This driver uses a global lock to protect the list of enumerated DMA
remapping units. It is necessary due to the driver's support for dynamic
addition and removal of remapping units at runtime.

Two distinct code paths require iteration over this remapping unit list:

- Device registration and probing: the driver iterates the list to
  register each remapping unit with the upper layer IOMMU framework
  and subsequently probe the devices managed by that unit.
- Global configuration: Upper layer components may also iterate the list
  to apply configuration changes.

The lock acquisition order between these two code paths was reversed. This
caused lockdep warnings, indicating a risk of deadlock. Fix this warning
by releasing the global lock before invoking upper layer interfaces for
device registration.

Fixes: b150654 ("iommu/vt-d: Fix suspicious RCU usage")
Closes: https://lore.kernel.org/linux-iommu/SJ1PR11MB612953431F94F18C954C4A9CB9D32@SJ1PR11MB6129.namprd11.prod.outlook.com/
Tested-by: Chaitanya Kumar Borah <[email protected]>
Cc: [email protected]
Signed-off-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
[ Upstream commit 6260406 ]

In ThinPro, we use the convention <upstream_ver>+hp<patchlevel> for
the kernel package. This does not have a dash in the name or version.
This is built by editing ".version" before a build, and setting
EXTRAVERSION="+hp" and KDEB_PKGVERSION make variables:

    echo 68 > .version
    make -j<n> EXTRAVERSION="+hp" bindeb-pkg KDEB_PKGVERSION=6.12.2+hp69

    .deb name: linux-image-6.12.2+hp_6.12.2+hp69_amd64.deb

Since commit 7d4f07d ("kbuild: deb-pkg: squash
scripts/package/deb-build-option to debian/rules"), this no longer
works. The deb build logic changed, even though, the commit message
implies that the logic should be unmodified.

Before, KBUILD_BUILD_VERSION was not set if the KDEB_PKGVERSION did
not contain a dash. After the change KBUILD_BUILD_VERSION is always
set to KDEB_PKGVERSION. Since this determines UTS_VERSION, the uname
output to look off:

    (now)      uname -a: version 6.12.2+hp ... #6.12.2+hp69
    (expected) uname -a: version 6.12.2+hp ... #69

Update the debian/rules logic to restore the original behavior.

Fixes: 7d4f07d ("kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules")
Signed-off-by: Alexandru Gagniuc <[email protected]>
Reviewed-by: Nicolas Schier <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
commit 93ae6e6 upstream.

We have recently seen report of lockdep circular lock dependency warnings
on platforms like Skylake and Kabylake:

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc6-CI_DRM_16276-gca2c04fe76e8+ #1 Not tainted
 ------------------------------------------------------
 swapper/0/1 is trying to acquire lock:
 ffffffff8360ee48 (iommu_probe_device_lock){+.+.}-{3:3},
   at: iommu_probe_device+0x1d/0x70

 but task is already holding lock:
 ffff888102c7efa8 (&device->physical_node_lock){+.+.}-{3:3},
   at: intel_iommu_init+0xe75/0x11f0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #6 (&device->physical_node_lock){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        intel_iommu_init+0xe75/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #5 (dmar_global_lock){++++}-{3:3}:
        down_read+0x43/0x1d0
        enable_drhd_fault_handling+0x21/0x110
        cpuhp_invoke_callback+0x4c6/0x870
        cpuhp_issue_call+0xbf/0x1f0
        __cpuhp_setup_state_cpuslocked+0x111/0x320
        __cpuhp_setup_state+0xb0/0x220
        irq_remap_enable_fault_handling+0x3f/0xa0
        apic_intr_mode_init+0x5c/0x110
        x86_late_time_init+0x24/0x40
        start_kernel+0x895/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #4 (cpuhp_state_mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __cpuhp_setup_state_cpuslocked+0x67/0x320
        __cpuhp_setup_state+0xb0/0x220
        page_alloc_init_cpuhp+0x2d/0x60
        mm_core_init+0x18/0x2c0
        start_kernel+0x576/0xbd0
        x86_64_start_reservations+0x18/0x30
        x86_64_start_kernel+0xbf/0x110
        common_startup_64+0x13e/0x141

 -> #3 (cpu_hotplug_lock){++++}-{0:0}:
        __cpuhp_state_add_instance+0x4f/0x220
        iova_domain_init_rcaches+0x214/0x280
        iommu_setup_dma_ops+0x1a4/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&domain->iova_cookie->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_setup_dma_ops+0x16b/0x710
        iommu_device_register+0x17d/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&group->mutex){+.+.}-{3:3}:
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        __iommu_probe_device+0x24c/0x4e0
        probe_iommu_group+0x2b/0x50
        bus_for_each_dev+0x7d/0xe0
        iommu_device_register+0xe1/0x260
        intel_iommu_init+0xda4/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 (iommu_probe_device_lock){+.+.}-{3:3}:
        __lock_acquire+0x1637/0x2810
        lock_acquire+0xc9/0x300
        __mutex_lock+0xb4/0xe40
        mutex_lock_nested+0x1b/0x30
        iommu_probe_device+0x1d/0x70
        intel_iommu_init+0xe90/0x11f0
        pci_iommu_init+0x13/0x70
        do_one_initcall+0x62/0x3f0
        kernel_init_freeable+0x3da/0x6a0
        kernel_init+0x1b/0x200
        ret_from_fork+0x44/0x70
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

 Chain exists of:
   iommu_probe_device_lock --> dmar_global_lock -->
     &device->physical_node_lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&device->physical_node_lock);
                                lock(dmar_global_lock);
                                lock(&device->physical_node_lock);
   lock(iommu_probe_device_lock);

  *** DEADLOCK ***

This driver uses a global lock to protect the list of enumerated DMA
remapping units. It is necessary due to the driver's support for dynamic
addition and removal of remapping units at runtime.

Two distinct code paths require iteration over this remapping unit list:

- Device registration and probing: the driver iterates the list to
  register each remapping unit with the upper layer IOMMU framework
  and subsequently probe the devices managed by that unit.
- Global configuration: Upper layer components may also iterate the list
  to apply configuration changes.

The lock acquisition order between these two code paths was reversed. This
caused lockdep warnings, indicating a risk of deadlock. Fix this warning
by releasing the global lock before invoking upper layer interfaces for
device registration.

Fixes: b150654 ("iommu/vt-d: Fix suspicious RCU usage")
Closes: https://lore.kernel.org/linux-iommu/SJ1PR11MB612953431F94F18C954C4A9CB9D32@SJ1PR11MB6129.namprd11.prod.outlook.com/
Tested-by: Chaitanya Kumar Borah <[email protected]>
Cc: [email protected]
Signed-off-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 26, 2025
[ Upstream commit 9a0e6f1 ]

syzkaller triggered an oversized kvmalloc() warning.
Silence it by adding __GFP_NOWARN.

syzkaller log:
 WARNING: CPU: 7 PID: 518 at mm/util.c:665 __kvmalloc_node_noprof+0x175/0x180
 CPU: 7 UID: 0 PID: 518 Comm: c_repro Not tainted 6.11.0-rc6+ #6
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 RIP: 0010:__kvmalloc_node_noprof+0x175/0x180
 RSP: 0018:ffffc90001e67c10 EFLAGS: 00010246
 RAX: 0000000000000100 RBX: 0000000000000400 RCX: ffffffff8149d46b
 RDX: 0000000000000000 RSI: ffff8881030fae80 RDI: 0000000000000002
 RBP: 000000712c800000 R08: 0000000000000100 R09: 0000000000000000
 R10: ffffc90001e67c10 R11: 0030ae0601000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000000
 FS:  00007fde79159740(0000) GS:ffff88813bdc0000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000020000180 CR3: 0000000105eb4005 CR4: 00000000003706b0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  <TASK>
  ib_umem_odp_get+0x1f6/0x390
  mlx5_ib_reg_user_mr+0x1e8/0x450
  ib_uverbs_reg_mr+0x28b/0x440
  ib_uverbs_write+0x7d3/0xa30
  vfs_write+0x1ac/0x6c0
  ksys_write+0x134/0x170
  ? __sanitizer_cov_trace_pc+0x1c/0x50
  do_syscall_64+0x50/0x110
  entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fixes: 3782495 ("RDMA/odp: Use kvcalloc for the dma_list and page_list")
Signed-off-by: Shay Drory <[email protected]>
Link: https://patch.msgid.link/c6cb92379de668be94894f49c2cfa40e73f94d56.1742388096.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
popcornmix pushed a commit that referenced this issue Apr 28, 2025
[ Upstream commit 9a0e6f1 ]

syzkaller triggered an oversized kvmalloc() warning.
Silence it by adding __GFP_NOWARN.

syzkaller log:
 WARNING: CPU: 7 PID: 518 at mm/util.c:665 __kvmalloc_node_noprof+0x175/0x180
 CPU: 7 UID: 0 PID: 518 Comm: c_repro Not tainted 6.11.0-rc6+ #6
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 RIP: 0010:__kvmalloc_node_noprof+0x175/0x180
 RSP: 0018:ffffc90001e67c10 EFLAGS: 00010246
 RAX: 0000000000000100 RBX: 0000000000000400 RCX: ffffffff8149d46b
 RDX: 0000000000000000 RSI: ffff8881030fae80 RDI: 0000000000000002
 RBP: 000000712c800000 R08: 0000000000000100 R09: 0000000000000000
 R10: ffffc90001e67c10 R11: 0030ae0601000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000000
 FS:  00007fde79159740(0000) GS:ffff88813bdc0000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000020000180 CR3: 0000000105eb4005 CR4: 00000000003706b0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  <TASK>
  ib_umem_odp_get+0x1f6/0x390
  mlx5_ib_reg_user_mr+0x1e8/0x450
  ib_uverbs_reg_mr+0x28b/0x440
  ib_uverbs_write+0x7d3/0xa30
  vfs_write+0x1ac/0x6c0
  ksys_write+0x134/0x170
  ? __sanitizer_cov_trace_pc+0x1c/0x50
  do_syscall_64+0x50/0x110
  entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fixes: 3782495 ("RDMA/odp: Use kvcalloc for the dma_list and page_list")
Signed-off-by: Shay Drory <[email protected]>
Link: https://patch.msgid.link/c6cb92379de668be94894f49c2cfa40e73f94d56.1742388096.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
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