syzbot

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BUG: KCSAN: data-race in n_tty_poll / tty_set_termios

write to 0xffff888135e49114 of 4 bytes by task 422 on cpu 0:
 unset_locked_termios drivers/tty/tty_ioctl.c:233 [inline]
 tty_set_termios+0x1d3/0x8b0 drivers/tty/tty_ioctl.c:355
 set_termios+0x384/0x3c0 drivers/tty/tty_ioctl.c:438
 tty_mode_ioctl+0x5a1/0x690
 n_tty_ioctl_helper+0x83/0x450 drivers/tty/tty_ioctl.c:903
 n_tty_ioctl+0xfc/0x1f0 drivers/tty/n_tty.c:2421
 tty_ioctl+0xaf5/0x1130 drivers/tty/tty_io.c:2814
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 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 0xffff888135e49114 of 4 bytes by task 421 on cpu 1:
 input_available_p drivers/tty/n_tty.c:1870 [inline]
 n_tty_poll+0x2ab/0x4a0 drivers/tty/n_tty.c:2368
 tty_poll+0xa7/0x140 drivers/tty/tty_io.c:2227
 vfs_poll include/linux/poll.h:90 [inline]
 __io_arm_poll_handler+0x1a8/0x780 fs/io_uring.c:5621
 io_poll_add+0x79/0x4c0 fs/io_uring.c:5888
 io_issue_sqe+0x112c/0x53b0 fs/io_uring.c:6686
 __io_queue_sqe+0x20/0x440 fs/io_uring.c:7022
 io_queue_sqe fs/io_uring.c:7064 [inline]
 io_submit_sqe+0x77a/0x47d3 fs/io_uring.c:7267
 io_submit_sqes+0x25d/0x670 fs/io_uring.c:7373
 __do_sys_io_uring_enter fs/io_uring.c:10076 [inline]
 __se_sys_io_uring_enter+0x212/0xb00 fs/io_uring.c:10018
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10018
 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: 0x00008a3b -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 421 Comm: syz-executor.5 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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