syzbot

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BUG: KCSAN: data-race in __io_cqring_fill_event / io_drain_req

write to 0xffff88813e7c7400 of 4 bytes by task 19872 on cpu 0:
 io_get_cqe fs/io_uring.c:1580 [inline]
 __io_cqring_fill_event+0xfb/0x350 fs/io_uring.c:1764
 io_req_complete_post+0x4d/0x640 fs/io_uring.c:1787
 io_issue_sqe+0x6145/0x67b0
 io_wq_submit_work+0xf5/0x2c0 fs/io_uring.c:6800
 io_worker_handle_work+0x788/0xa20 fs/io-wq.c:515
 io_wqe_worker+0x1b9/0x540 fs/io-wq.c:566
 ret_from_fork+0x1f/0x30

read to 0xffff88813e7c7400 of 4 bytes by task 19871 on cpu 1:
 req_need_defer fs/io_uring.c:1345 [inline]
 io_drain_req+0x4c1/0x610 fs/io_uring.c:6522
 io_queue_sqe fs/io_uring.c:7004 [inline]
 io_submit_sqe+0x357e/0x3eb0 fs/io_uring.c:7184
 io_submit_sqes+0x505/0xde0 fs/io_uring.c:7290
 __do_sys_io_uring_enter fs/io_uring.c:9992 [inline]
 __se_sys_io_uring_enter+0x20d/0xb30 fs/io_uring.c:9934
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:9934
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19871 Comm: syz-executor.2 Tainted: G        W         5.15.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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