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BUG: KCSAN: data-race in __io_cqring_fill_event / io_drain_req

write to 0xffff88810704ba00 of 4 bytes by task 6656 on cpu 1:
 io_get_cqe fs/io_uring.c:1695 [inline]
 __io_cqring_fill_event+0xf9/0x380 fs/io_uring.c:1873
 io_req_complete_post+0x4b/0x5d0 fs/io_uring.c:1896
 io_issue_sqe+0x3f53/0x55e0
 io_wq_submit_work+0x1c5/0x370 fs/io_uring.c:6836
 io_worker_handle_work+0x4ca/0xbd0 fs/io-wq.c:574
 io_wqe_worker+0x1bc/0x4f0 fs/io-wq.c:630
 ret_from_fork+0x1f/0x30

read to 0xffff88810704ba00 of 4 bytes by task 6653 on cpu 0:
 req_need_defer fs/io_uring.c:1461 [inline]
 io_drain_req+0x3a9/0x4e6 fs/io_uring.c:6543
 io_queue_sqe_fallback fs/io_uring.c:7045 [inline]
 io_queue_sqe fs/io_uring.c:7062 [inline]
 io_submit_sqe+0x44ca/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

value changed: 0x00000003 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6653 Comm: syz-executor.0 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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