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BUG: KCSAN: data-race in n_tty_flush_buffer / n_tty_lookahead_flow_ctrl

write to 0xffffc900002eb270 of 8 bytes by task 13337 on cpu 1:
 reset_buffer_flags drivers/tty/n_tty.c:340 [inline]
 n_tty_flush_buffer+0x9b/0x180 drivers/tty/n_tty.c:371
 tty_ldisc_hangup+0x72/0x470 drivers/tty/tty_ldisc.c:694
 __tty_hangup+0x3e4/0x560 drivers/tty/tty_io.c:631
 tty_vhangup drivers/tty/tty_io.c:701 [inline]
 tty_ioctl+0x46a/0x940 drivers/tty/tty_io.c:2715
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read-write to 0xffffc900002eb270 of 8 bytes by task 45 on cpu 0:
 n_tty_lookahead_flow_ctrl+0x4f/0x2f0 drivers/tty/n_tty.c:1490
 tty_port_default_lookahead_buf+0x81/0xb0 drivers/tty/tty_port.c:61
 lookahead_bufs drivers/tty/tty_buffer.c:498 [inline]
 flush_to_ldisc+0x32d/0x460 drivers/tty/tty_buffer.c:568
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

value changed: 0x000000000000119b -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 45 Comm: kworker/u4:3 Tainted: G        W          6.1.0-syzkaller-14321-g0a924817d2ed-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events_unbound flush_to_ldisc
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