[moderation] [io-uring?] KCSAN: data-race in io_wq_activate_free_worker / io_wq_worker

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 49a73b1652c5 Merge tag 'firewire-fixes-6.9-rc6' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=170fa228980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c3beef2aff822313
dashboard link: https://syzkaller.appspot.com/bug?extid=5ddf081d8c58435988bc
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/869474934b87/disk-49a73b16.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d7e932324bfd/vmlinux-49a73b16.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2aedff3b667/bzImage-49a73b16.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5ddf08...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in io_wq_activate_free_worker / io_wq_worker

write to 0xffff88812055d304 of 4 bytes by task 6377 on cpu 0:
io_wq_worker+0x81/0x730 io_uring/io-wq.c:634
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff88812055d304 of 4 bytes by task 6372 on cpu 1:
io_wq_get_acct io_uring/io-wq.c:168 [inline]
io_wq_activate_free_worker+0xfa/0x250 io_uring/io-wq.c:285
io_wq_enqueue+0x25e/0x440 io_uring/io-wq.c:947
io_queue_iowq+0x1d6/0x320 io_uring/io_uring.c:523
io_queue_sqe_fallback+0x87/0xe0 io_uring/io_uring.c:2143
io_submit_sqe io_uring/io_uring.c:2372 [inline]
io_submit_sqes+0xc4b/0x10a0 io_uring/io_uring.c:2492
__do_sys_io_uring_enter io_uring/io_uring.c:3668 [inline]
__se_sys_io_uring_enter+0x1d1/0x17f0 io_uring/io_uring.c:3603
__x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3603
x64_sys_call+0x263/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:427
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000c -> 0x0000000f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6372 Comm: syz-executor.3 Not tainted 6.9.0-rc6-syzkaller-00113-g49a73b1652c5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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[syzbot]

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