================================================================== BUG: KCSAN: data-race in __process_echoes / n_tty_receive_char_special write to 0xffffc9000032a687 of 1 bytes by task 18639 on cpu 1: add_echo_byte drivers/tty/n_tty.c:840 [inline] echo_char_raw drivers/tty/n_tty.c:920 [inline] eraser drivers/tty/n_tty.c:1082 [inline] n_tty_receive_char_special+0x1269/0x3ac0 drivers/tty/n_tty.c:1313 n_tty_receive_buf_fast drivers/tty/n_tty.c:1607 [inline] __receive_buf drivers/tty/n_tty.c:1641 [inline] n_tty_receive_buf_common+0xe0c/0x1e20 drivers/tty/n_tty.c:1740 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1769 tiocsti drivers/tty/tty_io.c:2315 [inline] tty_ioctl+0x968/0x1120 drivers/tty/tty_io.c:2721 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_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffc9000032a687 of 1 bytes by task 1783 on cpu 0: echo_buf drivers/tty/n_tty.c:150 [inline] __process_echoes+0x535/0x660 drivers/tty/n_tty.c:755 commit_echoes drivers/tty/n_tty.c:791 [inline] n_tty_receive_char_fast drivers/tty/n_tty.c:1446 [inline] n_tty_receive_buf_fast drivers/tty/n_tty.c:1606 [inline] __receive_buf drivers/tty/n_tty.c:1641 [inline] n_tty_receive_buf_common+0x14ad/0x1e20 drivers/tty/n_tty.c:1740 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1775 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:461 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:481 [inline] flush_to_ldisc+0x1c5/0x2c0 drivers/tty/tty_buffer.c:533 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276 worker_thread+0x636/0xae0 kernel/workqueue.c:2422 kthread+0x1d0/0x1f0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1783 Comm: kworker/u4:4 Not tainted 5.13.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc ==================================================================