syzbot


KCSAN: data-race in do_epoll_wait / ep_poll_callback (3)

Status: auto-closed as invalid on 2021/05/17 11:16
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 672d, last: 672d
similar bugs (7):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (7) 1 361d 361d 0/24 auto-closed as invalid on 2022/03/12 11:24
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (6) 1 403d 403d 0/24 auto-closed as invalid on 2022/01/29 14:05
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (2) 2 724d 727d 0/24 auto-closed as invalid on 2021/03/14 02:07
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (5) 2 509d 519d 0/24 auto-closed as invalid on 2021/10/15 22:14
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (4) 1 602d 602d 0/24 auto-closed as invalid on 2021/07/14 13:56
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback (8) 1 311d 311d 0/24 auto-closed as invalid on 2022/05/01 05:30
upstream KCSAN: data-race in do_epoll_wait / ep_poll_callback 221 912d 949d 0/24 auto-closed as invalid on 2020/08/31 10:40

Sample crash report:
==================================================================
BUG: KCSAN: data-race in do_epoll_wait / ep_poll_callback

write to 0xffff888024d27168 of 4 bytes by task 29692 on cpu 0:
 ep_send_events fs/eventpoll.c:1692 [inline]
 ep_poll fs/eventpoll.c:1792 [inline]
 do_epoll_wait+0x843/0xf00 fs/eventpoll.c:2220
 __do_sys_epoll_wait fs/eventpoll.c:2232 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2227 [inline]
 __x64_sys_epoll_wait+0xf6/0x120 fs/eventpoll.c:2227
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888024d27168 of 4 bytes by task 29695 on cpu 1:
 ep_poll_callback+0x415/0x4e0 fs/eventpoll.c:1200
 __wake_up_common+0xbc/0x130 kernel/sched/wait.c:108
 __wake_up_common_lock kernel/sched/wait.c:138 [inline]
 __wake_up+0x80/0xc0 kernel/sched/wait.c:157
 tty_ldisc_lock drivers/tty/tty_ldisc.c:336 [inline]
 tty_ldisc_hangup+0x1b1/0x4b0 drivers/tty/tty_ldisc.c:745
 __tty_hangup+0x467/0x610 drivers/tty/tty_io.c:639
 tty_vhangup drivers/tty/tty_io.c:712 [inline]
 tty_ioctl+0x59a/0x10c0 drivers/tty/tty_io.c:2742
 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+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 29695 Comm: syz-executor.2 Tainted: G        W         5.12.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-upstream-kcsan-gce 2021/03/31 08:49 upstream 5e46d1b78a03 6a81331a .config console log report info KCSAN: data-race in do_epoll_wait / ep_poll_callback
* Struck through repros no longer work on HEAD.