bpftool: fix build failure #52
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Master branch: 2bab48c patch https://patchwork.ozlabs.org/project/netdev/patch/[email protected]/ applied successfully |
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Master branch: d72714c patch https://patchwork.ozlabs.org/project/netdev/patch/[email protected]/ applied successfully |
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make -C tools/testing/selftests/bpf -j20
I hit the following errors:
...
GEN /net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-gen.8
<stdin>:75: (WARNING/2) Block quote ends without a blank line; unexpected unindent.
<stdin>:71: (WARNING/2) Literal block ends without a blank line; unexpected unindent.
<stdin>:85: (WARNING/2) Literal block ends without a blank line; unexpected unindent.
<stdin>:57: (WARNING/2) Block quote ends without a blank line; unexpected unindent.
<stdin>:66: (WARNING/2) Literal block ends without a blank line; unexpected unindent.
<stdin>:109: (WARNING/2) Literal block ends without a blank line; unexpected unindent.
<stdin>:175: (WARNING/2) Literal block ends without a blank line; unexpected unindent.
<stdin>:273: (WARNING/2) Literal block ends without a blank line; unexpected unindent.
make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-perf.8] Error 12
make[1]: *** Waiting for unfinished jobs....
make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-iter.8] Error 12
make[1]: *** [/net-next/tools/testing/selftests/bpf/tools/build/bpftool/Documentation/bpftool-struct_ops.8] Error 12
...
I am using:
-bash-4.4$ rst2man --version
rst2man (Docutils 0.11 [repository], Python 2.7.5, on linux2)
-bash-4.4$
The Makefile generated final .rst file (e.g., bpftool-cgroup.rst) looks like
...
ID AttachType AttachFlags Name
\n SEE ALSO\n========\n\t**bpf**\ (2),\n\t**bpf-helpers**\
(7),\n\t**bpftool**\ (8),\n\t**bpftool-btf**\
(8),\n\t**bpftool-feature**\ (8),\n\t**bpftool-gen**\
(8),\n\t**bpftool-iter**\ (8),\n\t**bpftool-link**\
(8),\n\t**bpftool-map**\ (8),\n\t**bpftool-net**\
(8),\n\t**bpftool-perf**\ (8),\n\t**bpftool-prog**\
(8),\n\t**bpftool-struct_ops**\ (8)\n
The rst2man generated .8 file looks like
Literal block ends without a blank line; unexpected unindent.
.sp
n SEEALSOn========nt**bpf**(2),nt**bpf\-helpers**(7),nt**bpftool**(8),nt**bpftool\-btf**(8),nt**
bpftool\-feature**(8),nt**bpftool\-gen**(8),nt**bpftool\-iter**(8),nt**bpftool\-link**(8),nt**
bpftool\-map**(8),nt**bpftool\-net**(8),nt**bpftool\-perf**(8),nt**bpftool\-prog**(8),nt**
bpftool\-struct_ops**(8)n
Looks like that particular version of rst2man prefers to have actual new line
instead of \n.
Since `echo -e` may not be available in some environment, let us use `printf`.
Format string "%b" is used for `printf` to ensure all escape characters are
interpretted properly.
Cc: Quentin Monnet <[email protected]>
Suggested-by: Andrii Nakryiko <[email protected]>
Fixes: 18841da ("tools: bpftool: Automate generation for "SEE ALSO" sections in man pages")
Signed-off-by: Yonghong Song <[email protected]>
---
tools/bpf/bpftool/Documentation/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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Master branch: bf74a37 patch https://patchwork.ozlabs.org/project/netdev/patch/[email protected]/ applied successfully |
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At least one diff in series https://patchwork.ozlabs.org/project/netdev/list/?series=201644 irrelevant now. Closing PR. |
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Feb 13, 2021
Syzkaller was able to trigger the following splat again: WARNING: CPU: 1 PID: 12512 at net/mptcp/protocol.c:761 mptcp_reset_timer+0x12a/0x160 net/mptcp/protocol.c:761 Modules linked in: CPU: 1 PID: 12512 Comm: kworker/1:6 Not tainted 5.10.0-rc6 #52 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:mptcp_reset_timer+0x12a/0x160 net/mptcp/protocol.c:761 Code: e8 4b 0c ad ff e8 56 21 88 fe 48 b8 00 00 00 00 00 fc ff df 48 c7 04 03 00 00 00 00 48 83 c4 40 5b 5d 41 5c c3 e8 36 21 88 fe <0f> 0b 41 bc c8 00 00 00 eb 98 e8 e7 b1 af fe e9 30 ff ff ff 48 c7 RSP: 0018:ffffc900018c7c68 EFLAGS: 00010293 RAX: ffff888108cb1c80 RBX: 1ffff92000318f8d RCX: ffffffff82ad0307 RDX: 0000000000000000 RSI: ffffffff82ad036a RDI: 0000000000000007 RBP: ffff888113e2d000 R08: ffff888108cb1c80 R09: ffffed10227c5ab7 R10: ffff888113e2d5b7 R11: ffffed10227c5ab6 R12: 0000000000000000 R13: ffff88801f100000 R14: ffff888113e2d5b0 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88811b500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd76a874ef8 CR3: 000000001689c005 CR4: 0000000000170ee0 Call Trace: mptcp_worker+0xaa4/0x1560 net/mptcp/protocol.c:2334 process_one_work+0x8d3/0x1200 kernel/workqueue.c:2272 worker_thread+0x9c/0x1090 kernel/workqueue.c:2418 kthread+0x303/0x410 kernel/kthread.c:292 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:296 The mptcp_worker tries to update the MPTCP retransmission timer even if such timer is not currently scheduled. The mptcp_rtx_head() return value is bogus: we can have enqueued data not yet transmitted. The above may additionally cause spurious, unneeded MPTCP-level retransmissions. Fix the issue adding an explicit clearing of the rtx queue before trying to retransmit and checking for unacked data. Additionally drop an unneeded timer stop call and the unused mptcp_rtx_tail() helper. Reported-by: Christoph Paasch <[email protected]> Fixes: 6e628cd ("mptcp: use mptcp release_cb for delayed tasks") Signed-off-by: Paolo Abeni <[email protected]> Signed-off-by: Mat Martineau <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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The inline assembly for arm64's cmpxchg_double*() implementations use a +Q constraint to hazard against other accesses to the memory location being exchanged. However, the pointer passed to the constraint is a pointer to unsigned long, and thus the hazard only applies to the first 8 bytes of the location. GCC can take advantage of this, assuming that other portions of the location are unchanged, leading to a number of potential problems. This is similar to what we fixed back in commit: fee960b ("arm64: xchg: hazard against entire exchange variable") ... but we forgot to adjust cmpxchg_double*() similarly at the same time. The same problem applies, as demonstrated with the following test: | struct big { | u64 lo, hi; | } __aligned(128); | | unsigned long foo(struct big *b) | { | u64 hi_old, hi_new; | | hi_old = b->hi; | cmpxchg_double_local(&b->lo, &b->hi, 0x12, 0x34, 0x56, 0x78); | hi_new = b->hi; | | return hi_old ^ hi_new; | } ... which GCC 12.1.0 compiles as: | 0000000000000000 <foo>: | 0: d503233f paciasp | 4: aa0003e4 mov x4, x0 | 8: 1400000e b 40 <foo+0x40> | c: d2800240 mov x0, #0x12 // #18 | 10: d2800681 mov x1, #0x34 // #52 | 14: aa0003e5 mov x5, x0 | 18: aa0103e6 mov x6, x1 | 1c: d2800ac2 mov x2, #0x56 // #86 | 20: d2800f03 mov x3, #0x78 // #120 | 24: 48207c82 casp x0, x1, x2, x3, [x4] | 28: ca050000 eor x0, x0, x5 | 2c: ca060021 eor x1, x1, x6 | 30: aa010000 orr x0, x0, x1 | 34: d2800000 mov x0, #0x0 // #0 <--- BANG | 38: d50323bf autiasp | 3c: d65f03c0 ret | 40: d2800240 mov x0, #0x12 // #18 | 44: d2800681 mov x1, #0x34 // #52 | 48: d2800ac2 mov x2, #0x56 // #86 | 4c: d2800f03 mov x3, #0x78 // #120 | 50: f9800091 prfm pstl1strm, [x4] | 54: c87f1885 ldxp x5, x6, [x4] | 58: ca0000a5 eor x5, x5, x0 | 5c: ca0100c6 eor x6, x6, x1 | 60: aa0600a6 orr x6, x5, x6 | 64: b5000066 cbnz x6, 70 <foo+0x70> | 68: c8250c82 stxp w5, x2, x3, [x4] | 6c: 35ffff45 cbnz w5, 54 <foo+0x54> | 70: d2800000 mov x0, #0x0 // #0 <--- BANG | 74: d50323bf autiasp | 78: d65f03c0 ret Notice that at the lines with "BANG" comments, GCC has assumed that the higher 8 bytes are unchanged by the cmpxchg_double() call, and that `hi_old ^ hi_new` can be reduced to a constant zero, for both LSE and LL/SC versions of cmpxchg_double(). This patch fixes the issue by passing a pointer to __uint128_t into the +Q constraint, ensuring that the compiler hazards against the entire 16 bytes being modified. With this change, GCC 12.1.0 compiles the above test as: | 0000000000000000 <foo>: | 0: f9400407 ldr x7, [x0, #8] | 4: d503233f paciasp | 8: aa0003e4 mov x4, x0 | c: 1400000f b 48 <foo+0x48> | 10: d2800240 mov x0, #0x12 // #18 | 14: d2800681 mov x1, #0x34 // #52 | 18: aa0003e5 mov x5, x0 | 1c: aa0103e6 mov x6, x1 | 20: d2800ac2 mov x2, #0x56 // #86 | 24: d2800f03 mov x3, #0x78 // #120 | 28: 48207c82 casp x0, x1, x2, x3, [x4] | 2c: ca050000 eor x0, x0, x5 | 30: ca060021 eor x1, x1, x6 | 34: aa010000 orr x0, x0, x1 | 38: f9400480 ldr x0, [x4, #8] | 3c: d50323bf autiasp | 40: ca0000e0 eor x0, x7, x0 | 44: d65f03c0 ret | 48: d2800240 mov x0, #0x12 // #18 | 4c: d2800681 mov x1, #0x34 // #52 | 50: d2800ac2 mov x2, #0x56 // #86 | 54: d2800f03 mov x3, #0x78 // #120 | 58: f9800091 prfm pstl1strm, [x4] | 5c: c87f1885 ldxp x5, x6, [x4] | 60: ca0000a5 eor x5, x5, x0 | 64: ca0100c6 eor x6, x6, x1 | 68: aa0600a6 orr x6, x5, x6 | 6c: b5000066 cbnz x6, 78 <foo+0x78> | 70: c8250c82 stxp w5, x2, x3, [x4] | 74: 35ffff45 cbnz w5, 5c <foo+0x5c> | 78: f9400480 ldr x0, [x4, #8] | 7c: d50323bf autiasp | 80: ca0000e0 eor x0, x7, x0 | 84: d65f03c0 ret ... sampling the high 8 bytes before and after the cmpxchg, and performing an EOR, as we'd expect. For backporting, I've tested this atop linux-4.9.y with GCC 5.5.0. Note that linux-4.9.y is oldest currently supported stable release, and mandates GCC 5.1+. Unfortunately I couldn't get a GCC 5.1 binary to run on my machines due to library incompatibilities. I've also used a standalone test to check that we can use a __uint128_t pointer in a +Q constraint at least as far back as GCC 4.8.5 and LLVM 3.9.1. Fixes: 5284e1b ("arm64: xchg: Implement cmpxchg_double") Fixes: e9a4b79 ("arm64: cmpxchg_dbl: patch in lse instructions when supported by the CPU") Reported-by: Boqun Feng <[email protected]> Link: https://lore.kernel.org/lkml/Y6DEfQXymYVgL3oJ@boqun-archlinux/ Reported-by: Peter Zijlstra <[email protected]> Link: https://lore.kernel.org/lkml/[email protected]/ Signed-off-by: Mark Rutland <[email protected]> Cc: [email protected] Cc: Arnd Bergmann <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Steve Capper <[email protected]> Cc: Will Deacon <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
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Pull request for series with
subject: bpftool: fix build failure
version: 3
url: https://patchwork.ozlabs.org/project/netdev/list/?series=201644