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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ddb4c3f25b7b Merge tag 'for-linus-6.9a-rc7-tag' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12973588980000
kernel config: https://syzkaller.appspot.com/x/.config?x=c3beef2aff822313
dashboard link: https://syzkaller.appspot.com/bug?extid=fb0d2b81f94bbc646cbf
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/3d645f06ab6c/disk-ddb4c3f2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7cc55089db0f/vmlinux-ddb4c3f2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0f90bd75f35d/bzImage-ddb4c3f2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fb0d2b...@syzkaller.appspotmail.com

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

write to 0xffff888116abbc04 of 4 bytes by task 19443 on cpu 0:
io_wq_worker_running+0x64/0xb0 io_uring/io-wq.c:702
schedule_timeout+0xca/0x2c0 kernel/time/timer.c:2582
io_wq_worker+0x35e/0x730 io_uring/io-wq.c:667
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 0xffff888116abbc04 of 4 bytes by task 19441 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: 0x0000000d -> 0x0000000b

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19441 Comm: syz-executor.4 Tainted: G W 6.9.0-rc6-syzkaller-00232-gddb4c3f25b7b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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