syzbot

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BUG: KCSAN: data-race in __io_cqring_fill_event / io_uring_poll

write to 0xffff888137246a00 of 4 bytes by task 10744 on cpu 1:
 io_get_cqe fs/io_uring.c:1695 [inline]
 __io_cqring_fill_event+0xf9/0x380 fs/io_uring.c:1873
 io_cqring_fill_event+0x28/0x30 fs/io_uring.c:1887
 __io_poll_complete fs/io_uring.c:5399 [inline]
 io_poll_add+0x143/0x4c0 fs/io_uring.c:5889
 io_issue_sqe+0xc92/0x55e0 fs/io_uring.c:6682
 __io_queue_sqe+0x20/0x440 fs/io_uring.c:7018
 io_queue_sqe fs/io_uring.c:7060 [inline]
 io_submit_sqe+0x77a/0x47d3 fs/io_uring.c:7263
 io_submit_sqes+0x25d/0x670 fs/io_uring.c:7369
 __do_sys_io_uring_enter fs/io_uring.c:10072 [inline]
 __se_sys_io_uring_enter+0x212/0xb00 fs/io_uring.c:10014
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10014
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888137246a00 of 4 bytes by task 10654 on cpu 0:
 __io_cqring_events fs/io_uring.c:1679 [inline]
 io_cqring_events fs/io_uring.c:2455 [inline]
 io_uring_poll+0xc6/0x146 fs/io_uring.c:9420
 vfs_poll include/linux/poll.h:90 [inline]
 io_poll_rewait fs/io_uring.c:5338 [inline]
 io_poll_task_func+0x12d/0x9d0 fs/io_uring.c:5414
 tctx_task_work+0x25a/0x410 fs/io_uring.c:2245
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_signal include/linux/tracehook.h:214 [inline]
 handle_signal_work kernel/entry/common.c:146 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x102/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000501 -> 0x00000515

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10654 Comm: syz-executor.3 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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