[moderation] [io-uring?] KCSAN: data-race in io_submit_sqes / io_uring_poll (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 96fca68c4fbf Merge tag 'nfsd-6.9-3' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15626c7d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=eaea34ec4c9b6fb6
dashboard link: https://syzkaller.appspot.com/bug?extid=ee59580af8baca3026ab
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/c847bdb99fa5/disk-96fca68c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7f1451b82626/vmlinux-96fca68c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dc96a83503e5/bzImage-96fca68c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ee5958...@syzkaller.appspotmail.com

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

read-write to 0xffff888126fad870 of 4 bytes by task 6103 on cpu 1:
io_get_sqe io_uring/io_uring.c:2432 [inline]
io_submit_sqes+0x23f/0x10a0 io_uring/io_uring.c:2483
__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

read to 0xffff888126fad870 of 4 bytes by task 6096 on cpu 0:
io_sqring_full io_uring/io_uring.h:291 [inline]
io_uring_poll+0xcf/0x190 io_uring/io_uring.c:2991
vfs_poll include/linux/poll.h:84 [inline]
__io_arm_poll_handler+0x229/0xf30 io_uring/poll.c:622
io_arm_poll_handler+0x3e6/0x590 io_uring/poll.c:758
io_queue_async+0x89/0x310 io_uring/io_uring.c:2089
io_queue_sqe io_uring/io_uring.c:2118 [inline]
io_req_task_submit+0xff/0x110 io_uring/io_uring.c:1510
io_handle_tw_list+0x1ef/0x240 io_uring/io_uring.c:1198
tctx_task_work_run+0x6c/0x1b0 io_uring/io_uring.c:1270
tctx_task_work+0x40/0x80 io_uring/io_uring.c:1288
task_work_run+0x13a/0x1a0 kernel/task_work.c:180
get_signal+0xeee/0x1080 kernel/signal.c:2683
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+0xda/0x1d0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00002264 -> 0x00002297

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6096 Comm: syz-executor.2 Not tainted 6.9.0-rc4-syzkaller-00031-g96fca68c4fbf #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