================================================================== BUG: KCSAN: data-race in n_tty_receive_char / start_tty write to 0xffff888130e9b5bc of 1 bytes by task 5142 on cpu 1: __start_tty drivers/tty/tty_io.c:803 [inline] start_tty+0x81/0x170 drivers/tty/tty_io.c:825 n_tty_receive_char_special drivers/tty/n_tty.c:1269 [inline] n_tty_receive_buf_standard drivers/tty/n_tty.c:1558 [inline] __receive_buf drivers/tty/n_tty.c:1577 [inline] n_tty_receive_buf_common+0x107c/0x4e70 drivers/tty/n_tty.c:1674 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1703 tiocsti drivers/tty/tty_io.c:2311 [inline] tty_ioctl+0x968/0x1120 drivers/tty/tty_io.c:2719 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888130e9b5bc of 1 bytes by task 1794 on cpu 0: n_tty_receive_char+0x3d/0x6c0 drivers/tty/n_tty.c:1401 n_tty_receive_buf_standard drivers/tty/n_tty.c:1560 [inline] __receive_buf drivers/tty/n_tty.c:1577 [inline] n_tty_receive_buf_common+0xf2e/0x4e70 drivers/tty/n_tty.c:1674 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1709 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:471 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:491 [inline] flush_to_ldisc+0x1c5/0x2c0 drivers/tty/tty_buffer.c:543 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276 worker_thread+0x636/0xae0 kernel/workqueue.c:2422 kthread+0x262/0x280 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 value changed: 0x01 -> 0x00 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1794 Comm: kworker/u4:6 Tainted: G W 5.14.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc ==================================================================