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BUG: KCSAN: data-race in n_tty_receive_char / n_tty_write

write to 0xffffc90002839028 of 8 bytes by task 2250 on cpu 0:
 commit_echoes drivers/tty/n_tty.c:738 [inline]
 n_tty_receive_char+0x44e/0x6d0 drivers/tty/n_tty.c:1413
 n_tty_receive_buf_standard+0x563/0x3cb0 drivers/tty/n_tty.c:1582
 __receive_buf drivers/tty/n_tty.c:1616 [inline]
 n_tty_receive_buf_common+0x821/0xc10 drivers/tty/n_tty.c:1715
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1759
 tty_ldisc_receive_buf+0x66/0xf0 drivers/tty/tty_buffer.c:394
 tty_port_default_receive_buf+0x59/0x90 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:452 [inline]
 flush_to_ldisc+0x13a/0x330 drivers/tty/tty_buffer.c:502
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffc90002839028 of 8 bytes by task 5141 on cpu 1:
 process_echoes drivers/tty/n_tty.c:762 [inline]
 n_tty_write+0x178/0xb00 drivers/tty/n_tty.c:2352
 iterate_tty_write drivers/tty/tty_io.c:1008 [inline]
 file_tty_write+0x392/0x6a0 drivers/tty/tty_io.c:1056
 tty_write+0x25/0x30 drivers/tty/tty_io.c:1077
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57f/0x9a0 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000001b022 -> 0x000000000001b024

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5141 Comm: syz.1.579 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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