================================================================== BUG: KCSAN: data-race in tty_flip_buffer_push / tty_insert_flip_string_fixed_flag write to 0xffff888137c8bc08 of 4 bytes by task 20454 on cpu 1: tty_insert_flip_string_fixed_flag+0x15c/0x1c0 drivers/tty/tty_buffer.c:329 tty_insert_flip_string include/linux/tty_flip.h:41 [inline] pty_write+0xbc/0x120 drivers/tty/pty.c:122 tty_send_xchar+0x1ce/0x290 drivers/tty/tty_io.c:1168 n_tty_ioctl_helper+0x2d8/0x450 n_tty_ioctl+0xfc/0x1f0 drivers/tty/n_tty.c:2383 tty_ioctl+0xaf7/0x1130 drivers/tty/tty_io.c:2787 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888137c8bc08 of 4 bytes by task 27919 on cpu 0: tty_flip_buffer_push+0x28/0x60 drivers/tty/tty_buffer.c:552 pty_write+0xfe/0x120 drivers/tty/pty.c:126 tty_put_char+0x7f/0xa0 drivers/tty/tty_io.c:3144 __process_echoes+0x3bd/0x660 drivers/tty/n_tty.c:712 flush_echoes drivers/tty/n_tty.c:812 [inline] __receive_buf drivers/tty/n_tty.c:1551 [inline] n_tty_receive_buf_common+0x4c38/0x4e70 drivers/tty/n_tty.c:1645 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1680 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:451 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:471 [inline] flush_to_ldisc+0x1c5/0x300 drivers/tty/tty_buffer.c:521 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 worker_thread+0x616/0xa70 kernel/workqueue.c:2454 kthread+0x2c7/0x2e0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 value changed: 0x0000007d -> 0x0000007e Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 27919 Comm: kworker/u4:49 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc ==================================================================