syzbot

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BUG: KCSAN: data-race in __io_queue_proc / io_poll_wake

write to 0xffff88811671aba8 of 8 bytes by task 14882 on cpu 0:
 io_poll_wake+0x1f9/0x3b0 io_uring/poll.c:418
 __wake_up_common kernel/sched/wait.c:108 [inline]
 __wake_up_common_lock kernel/sched/wait.c:125 [inline]
 __wake_up+0x63/0xb0 kernel/sched/wait.c:146
 __receive_buf drivers/tty/n_tty.c:1641 [inline]
 n_tty_receive_buf_common+0x735/0xbe0 drivers/tty/n_tty.c:1723
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1769
 tty_ldisc_receive_buf+0x63/0xf0 drivers/tty/tty_buffer.c:387
 tty_port_default_receive_buf+0x59/0x90 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x148/0x340 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88811671aba8 of 8 bytes by task 25565 on cpu 1:
 __io_queue_proc+0x10a/0x280 io_uring/poll.c:471
 io_async_queue_proc+0x43/0x50 io_uring/poll.c:634
 poll_wait include/linux/poll.h:45 [inline]
 n_tty_poll+0x7a/0x450 drivers/tty/n_tty.c:2451
 tty_poll+0x76/0xf0 drivers/tty/tty_io.c:2199
 vfs_poll include/linux/poll.h:82 [inline]
 __io_arm_poll_handler+0x1ee/0xb70 io_uring/poll.c:581
 io_arm_apoll+0x3d2/0x4f0 io_uring/poll.c:691
 io_arm_poll_handler+0x131/0x160 io_uring/poll.c:720
 io_queue_async+0x25b/0x450 io_uring/io_uring.c:2004
 io_queue_sqe io_uring/io_uring.c:2032 [inline]
 io_submit_sqe io_uring/io_uring.c:2284 [inline]
 io_submit_sqes+0xa3c/0x1050 io_uring/io_uring.c:2397
 __do_sys_io_uring_enter io_uring/io_uring.c:3464 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3398
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3398
 x64_sys_call+0x2de1/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888119d22a08 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 25565 Comm: syz.0.8963 Not tainted 6.17.0-rc1-syzkaller-00199-gdfd4b508c8c6 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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