syzbot


KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common (4)

Status: auto-closed as invalid on 2022/06/02 02:02
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 223d, last: 223d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common (2) 4 427d 449d 0/24 auto-closed as invalid on 2021/11/10 16:29
upstream KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common (5) 1 143d 143d 0/24 auto-closed as invalid on 2022/08/21 08:44
upstream KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common 1 1036d 1036d 0/24 auto-closed as invalid on 2020/04/15 15:43
upstream KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common (3) 4 296d 346d 0/24 auto-closed as invalid on 2022/03/21 13:14
upstream KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common (6) 1 67d 67d 0/24 auto-obsoleted due to no activity on 2022/11/05 11:00

Sample crash report:
==================================================================
BUG: KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common

read to 0xffffc90001df105c of 1 bytes by task 2477 on cpu 0:
 n_tty_kick_worker+0x2d/0x160 drivers/tty/n_tty.c:204
 n_tty_read+0x4b6/0x10b0 drivers/tty/n_tty.c:2056
 iterate_tty_read drivers/tty/tty_io.c:858 [inline]
 tty_read+0x19d/0x420 drivers/tty/tty_io.c:933
 call_read_iter include/linux/fs.h:2044 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 vfs_read+0x5a5/0x6a0 fs/read_write.c:482
 ksys_read+0xe8/0x1a0 fs/read_write.c:620
 __do_sys_read fs/read_write.c:630 [inline]
 __se_sys_read fs/read_write.c:628 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:628
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffffc90001df105c of 1 bytes by task 1856 on cpu 1:
 n_tty_receive_buf_common+0x378/0x4c40 drivers/tty/n_tty.c:1635
 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+0x1ca/0x2f0 drivers/tty/tty_buffer.c:521
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 process_scheduled_works kernel/workqueue.c:2352 [inline]
 worker_thread+0x7cf/0xa70 kernel/workqueue.c:2438
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1856 Comm: kworker/u4:6 Not tainted 5.18.0-rc4-syzkaller-00064-g8f4dd16603ce-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/04/28 01:55 upstream 8f4dd16603ce 8a1f1f07 .config log report info KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common
* Struck through repros no longer work on HEAD.