syzbot


KCSAN: data-race in n_tty_kick_worker / n_tty_receive_buf_common (5)

Status: auto-closed as invalid on 2022/08/21 08:44
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 143d, last: 143d
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 (4) 1 223d 223d 0/24 auto-closed as invalid on 2022/06/02 02:02
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 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 0xffffc9000172905c of 1 bytes by task 6559 on cpu 1:
 n_tty_kick_worker+0x2d/0x160 drivers/tty/n_tty.c:204
 n_tty_check_unthrottle+0x17b/0x1c0 drivers/tty/n_tty.c:273
 n_tty_read+0xec6/0x1170 drivers/tty/n_tty.c:2225
 iterate_tty_read drivers/tty/tty_io.c:858 [inline]
 tty_read+0x19d/0x420 drivers/tty/tty_io.c:933
 __kernel_read+0x2c5/0x4f0 fs/read_write.c:440
 kernel_read+0xaa/0x160 fs/read_write.c:458
 p9_fd_read net/9p/trans_fd.c:263 [inline]
 p9_read_work+0x1f5/0x880 net/9p/trans_fd.c:298
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

write to 0xffffc9000172905c of 1 bytes by task 36 on cpu 0:
 n_tty_receive_buf_common+0x378/0x4c40 drivers/tty/n_tty.c:1648
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1693
 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:452
 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:472 [inline]
 flush_to_ldisc+0x1ca/0x2f0 drivers/tty/tty_buffer.c:522
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 36 Comm: kworker/u4:2 Tainted: G        W         5.19.0-rc6-syzkaller-00418-g972a278fe60c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
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 2022/07/17 08:42 upstream 972a278fe60c 95cb00d1 .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.