[moderation] [io-uring?] KCSAN: data-race in __se_sys_io_uring_enter / io_submit_sqes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a95f71ad3e2e Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=120b995a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=70c3ed59b49365c3
dashboard link: https://syzkaller.appspot.com/bug?extid=f5acdf7d4d926a1b4f7d
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [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/59161fbffbab/disk-a95f71ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1a0e7d4c6e66/vmlinux-a95f71ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e5755f320cce/bzImage-a95f71ad.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f5acdf...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __se_sys_io_uring_enter / io_submit_sqes

write to 0xffff8881438eb004 of 2 bytes by task 27617 on cpu 1:
io_init_req io_uring/io_uring.c:1770 [inline]
io_submit_sqe io_uring/io_uring.c:1875 [inline]
io_submit_sqes+0xca3/0x1270 io_uring/io_uring.c:2043
__io_sq_thread io_uring/sqpoll.c:233 [inline]
io_sq_thread+0x7f9/0x1310 io_uring/sqpoll.c:345
ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff8881438eb004 of 2 bytes by task 27620 on cpu 0:
__do_sys_io_uring_enter io_uring/io_uring.c:2624 [inline]
__se_sys_io_uring_enter+0x2e4/0xf50 io_uring/io_uring.c:2538
__x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:2538
x64_sys_call+0x1e16/0x3020 arch/x86/include/generated/asm/syscalls_64.h:427
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0200 -> 0x0608

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 27620 Comm: syz.7.7213 Tainted: G W syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================


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