syzbot

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BUG: KCSAN: data-race in __io_queue_proc / io_poll_wake

write to 0xffff88812f7827e8 of 8 bytes by task 1460 on cpu 1:
 io_poll_wake+0x1f9/0x3b0 io_uring/poll.c:420
 __wake_up_common kernel/sched/wait.c:89 [inline]
 __wake_up_common_lock kernel/sched/wait.c:106 [inline]
 __wake_up+0x66/0xb0 kernel/sched/wait.c:127
 n_tty_receive_handle_newline drivers/tty/n_tty.c:1250 [inline]
 n_tty_receive_char_canon drivers/tty/n_tty.c:1306 [inline]
 n_tty_receive_char_special drivers/tty/n_tty.c:1372 [inline]
 n_tty_receive_buf_standard+0x2011/0x2f10 drivers/tty/n_tty.c:1588
 __receive_buf drivers/tty/n_tty.c:1624 [inline]
 n_tty_receive_buf_common+0x805/0xbe0 drivers/tty/n_tty.c:1723
 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1763
 tiocsti+0x170/0x1d0 drivers/tty/tty_io.c:2299
 tty_ioctl+0x4a4/0xb80 drivers/tty/tty_io.c:2716
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:892
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:892
 x64_sys_call+0x19a8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812f7827e8 of 8 bytes by task 1451 on cpu 0:
 __io_queue_proc+0x10a/0x280 io_uring/poll.c:473
 io_async_queue_proc+0x43/0x50 io_uring/poll.c:636
 poll_wait include/linux/poll.h:45 [inline]
 n_tty_poll+0x7a/0x450 drivers/tty/n_tty.c:2451
 tty_poll+0x79/0xf0 drivers/tty/tty_io.c:2208
 vfs_poll include/linux/poll.h:82 [inline]
 __io_arm_poll_handler+0x1ee/0xb70 io_uring/poll.c:583
 io_arm_poll_handler+0x427/0x5b0 io_uring/poll.c:708
 io_queue_async+0x60/0x3e0 io_uring/io_uring.c:1945
 io_queue_sqe io_uring/io_uring.c:1971 [inline]
 io_submit_sqe io_uring/io_uring.c:2220 [inline]
 io_submit_sqes+0xa0c/0x1000 io_uring/io_uring.c:2337
 __do_sys_io_uring_enter io_uring/io_uring.c:3397 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3331
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3331
 x64_sys_call+0x28c8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88811660ea08 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 1451 Comm: syz.8.18997 Tainted: G        W           6.15.0-rc7-syzkaller-00099-g94305e83eccb #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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