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bpf: Fix warning for cast from restricted gfp_t in verifier #190

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Pull request for series with
subject: bpf: Fix warning for cast from restricted gfp_t in verifier
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=625260

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Master branch: d8dc09a
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=625260
version: 1

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Master branch: d56c9fe
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=625260
version: 1

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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=625260 irrelevant now. Closing PR.

@kernel-patches-bot kernel-patches-bot deleted the series/625260=>bpf-next branch March 21, 2022 20:45
kernel-patches-bot pushed a commit that referenced this pull request Jan 30, 2023
Ilya Leoshkevich says:

====================

v2: https://lore.kernel.org/bpf/[email protected]/#t
v2 -> v3:
- Make __arch_prepare_bpf_trampoline static.
  (Reported-by: kernel test robot <[email protected]>)
- Support both old- and new- style map definitions in sk_assign. (Alexei)
- Trim DENYLIST.s390x. (Alexei)
- Adjust s390x vmlinux path in vmtest.sh.
- Drop merged fixes.

v1: https://lore.kernel.org/bpf/[email protected]/#t
v1 -> v2:
- Fix core_read_macros, sk_assign, test_profiler, test_bpffs (24/31;
  I'm not quite happy with the fix, but don't have better ideas),
  and xdp_synproxy. (Andrii)
- Prettify liburandom_read and verify_pkcs7_sig fixes. (Andrii)
- Fix bpf_usdt_arg using barrier_var(); prettify barrier_var(). (Andrii)
- Change BPF_MAX_TRAMP_LINKS to enum and query it using BTF. (Andrii)
- Improve bpf_jit_supports_kfunc_call() description. (Alexei)
- Always check sign_extend() return value.
- Cc: Alexander Gordeev.

Hi,

This series implements poke, trampoline, kfunc, and mixing subprogs
and tailcalls on s390x.

The following failures still remain:

#82      get_stack_raw_tp:FAIL
get_stack_print_output:FAIL:user_stack corrupted user stack
Known issue:
We cannot reliably unwind userspace on s390x without DWARF.

#101     ksyms_module:FAIL
address of kernel function bpf_testmod_test_mod_kfunc is out of range
Known issue:
Kernel and modules are too far away from each other on s390x.

#190     stacktrace_build_id:FAIL
Known issue:
We cannot reliably unwind userspace on s390x without DWARF.

#281     xdp_metadata:FAIL
See patch 6.

None of these seem to be due to the new changes.

Best regards,
Ilya
====================

Signed-off-by: Alexei Starovoitov <[email protected]>
kernel-patches-daemon-bpf-rc bot pushed a commit that referenced this pull request Jul 6, 2023
We got a NULL pointer dereference issue below while running generic/475
I/O failure pressure test.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 PGD 0 P4D 0
 Oops: 0002 [#1] PREEMPT SMP PTI
 CPU: 1 PID: 15600 Comm: fsstress Not tainted 6.4.0-rc5-xfstests-00055-gd3ab1bca26b4 #190
 RIP: 0010:jbd2_journal_set_features+0x13d/0x430
 ...
 Call Trace:
  <TASK>
  ? __die+0x23/0x60
  ? page_fault_oops+0xa4/0x170
  ? exc_page_fault+0x67/0x170
  ? asm_exc_page_fault+0x26/0x30
  ? jbd2_journal_set_features+0x13d/0x430
  jbd2_journal_revoke+0x47/0x1e0
  __ext4_forget+0xc3/0x1b0
  ext4_free_blocks+0x214/0x2f0
  ext4_free_branches+0xeb/0x270
  ext4_ind_truncate+0x2bf/0x320
  ext4_truncate+0x1e4/0x490
  ext4_handle_inode_extension+0x1bd/0x2a0
  ? iomap_dio_complete+0xaf/0x1d0

The root cause is the journal super block had been failed to write out
due to I/O fault injection, it's uptodate bit was cleared by
end_buffer_write_sync() and didn't reset yet in jbd2_write_superblock().
And it raced by journal_get_superblock()->bh_read(), unfortunately, the
read IO is also failed, so the error handling in
journal_fail_superblock() unexpectedly clear the journal->j_sb_buffer,
finally lead to above NULL pointer dereference issue.

If the journal super block had been read and verified, there is no need
to call bh_read() read it again even if it has been failed to written
out. So the fix could be simply move buffer_verified(bh) in front of
bh_read(). Also remove a stale comment left in
jbd2_journal_check_used_features().

Fixes: 51bacdba23d8 ("jbd2: factor out journal initialization from journal_get_superblock()")
Reported-by: Theodore Ts'o <[email protected]>
Signed-off-by: Zhang Yi <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
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