syzbot

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BUG: KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common

write to 0xffffc9000c49505c of 1 bytes by task 24716 on cpu 0:
 n_tty_receive_buf_common+0x273/0xbf0 drivers/tty/n_tty.c:1701
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1746
 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:457
 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:515 [inline]
 flush_to_ldisc+0x1d9/0x470 drivers/tty/tty_buffer.c:565
 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:306

read to 0xffffc9000c49505c of 1 bytes by task 9518 on cpu 1:
 n_tty_kick_worker+0x2d/0x160 drivers/tty/n_tty.c:207
 n_tty_check_unthrottle+0x17b/0x1c0 drivers/tty/n_tty.c:276
 n_tty_read+0x606/0x1170 drivers/tty/n_tty.c:2159
 iterate_tty_read drivers/tty/tty_io.c:858 [inline]
 tty_read+0x19d/0x420 drivers/tty/tty_io.c:933
 do_iter_read+0x492/0x760 fs/read_write.c:796
 vfs_readv fs/read_write.c:916 [inline]
 do_readv+0x17b/0x2b0 fs/read_write.c:953
 __do_sys_readv fs/read_write.c:1044 [inline]
 __se_sys_readv fs/read_write.c:1041 [inline]
 __x64_sys_readv+0x41/0x50 fs/read_write.c:1041
 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

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9518 Comm: syz-executor.3 Not tainted 6.0.0-rc7-syzkaller-00180-g70575e77839f-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
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