KCSAN: data-race in do_con_write / n_tty_ioctl

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_con_write / n_tty_ioctl_helper (2) serial				1	1056d	1056d	0/26	auto-closed as invalid on 2021/07/08 06:06

================================================================== BUG: KCSAN: data-race in do_con_write / n_tty_ioctl_helper write to 0xffff88814e7ca1cc of 1 bytes by task 13868 on cpu 1: n_tty_ioctl_helper+0x106/0x4c0 drivers/tty/tty_ioctl.c:851 n_tty_ioctl+0x102/0x200 drivers/tty/n_tty.c:2486 tty_ioctl+0xa9b/0x1130 drivers/tty/tty_io.c:2810 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88814e7ca1cc of 1 bytes by task 13871 on cpu 0: do_con_write+0x1fb5/0x5d90 drivers/tty/vt/vt.c:2890 con_write+0x20/0x40 drivers/tty/vt/vt.c:3254 n_tty_write+0x39b/0xaf0 drivers/tty/n_tty.c:2376 do_tty_write drivers/tty/tty_io.c:1043 [inline] file_tty_write+0x409/0x660 drivers/tty/tty_io.c:1133 tty_write+0x24/0x30 drivers/tty/tty_io.c:1140 call_write_iter include/linux/fs.h:1977 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x69d/0x770 fs/read_write.c:605 ksys_write+0xce/0x180 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:667 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 13871 Comm: syz-executor.4 Not tainted 5.12.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================