[moderation] [io-uring?] KCSAN: data-race in io_req_defer_failed / io_wq_free_work (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7006fe2f7f78 Merge tag 'x86-urgent-2024-08-11' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16c83913980000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb57e6ebf675f9d2
dashboard link: https://syzkaller.appspot.com/bug?extid=dba7faa79d195e89e311
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [asml.s...@gmail.com ax...@kernel.dk io-u...@vger.kernel.org linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d01fe743c9d4/disk-7006fe2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d46915b6e0b3/vmlinux-7006fe2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5265c6a44a02/bzImage-7006fe2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dba7fa...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in io_req_defer_failed / io_wq_free_work

write to 0xffff888117aa6e48 of 8 bytes by task 7572 on cpu 0:
io_req_defer_failed+0x6e/0x280 io_uring/io_uring.c:906
io_req_task_cancel+0x21/0x30 io_uring/io_uring.c:1332
io_handle_tw_list+0x1b9/0x200 io_uring/io_uring.c:1034
tctx_task_work_run+0x6c/0x1b0 io_uring/io_uring.c:1106
tctx_task_work+0x40/0x80 io_uring/io_uring.c:1124
task_work_run+0x13a/0x1a0 kernel/task_work.c:228
get_signal+0xeee/0x1080 kernel/signal.c:2689
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888117aa6e48 of 8 bytes by task 7573 on cpu 1:
req_ref_put_and_test io_uring/refs.h:22 [inline]
io_wq_free_work+0x21/0x160 io_uring/io_uring.c:1750
io_worker_handle_work+0x4cb/0x9d0 io_uring/io-wq.c:603
io_wq_worker+0x286/0x820 io_uring/io-wq.c:654
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000000000c0059 -> 0x00000000004c0119

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7573 Comm: iou-wrk-7572 Not tainted 6.11.0-rc2-syzkaller-00315-g7006fe2f7f78 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.