syzbot


INFO: task hung in linkwatch_event

Status: public: reported C repro on 2019/04/10 16:14
Reported-by: syzbot+d5bfa41f359a671cd33d@syzkaller.appspotmail.com
First crash: 2229d, last: 1794d
Similar bugs (14)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in linkwatch_event (2) 1 814d 814d 0/1 auto-obsoleted due to no activity on 2022/11/19 11:58
android-44 INFO: task hung in linkwatch_event 6 2229d 2375d 0/2 auto-closed as invalid on 2019/03/05 13:11
linux-5.15 INFO: task hung in linkwatch_event 78 5d10h 277d 0/3 upstream: reported on 2024/01/11 11:32
upstream INFO: task hung in linkwatch_event (4) net C done 1763 now 79d 0/28 upstream: reported C repro on 2024/07/27 06:21
upstream INFO: task hung in linkwatch_event net C 82 1822d 2433d 0/28 closed as dup on 2018/02/14 15:33
linux-4.14 INFO: task hung in linkwatch_event 5 1498d 1625d 0/1 auto-closed as invalid on 2021/01/05 01:42
linux-4.19 INFO: task hung in linkwatch_event (2) C error 217 589d 1677d 0/1 upstream: reported C repro on 2020/03/11 20:12
upstream INFO: task hung in linkwatch_event (2) net C done done 1033 903d 1629d 20/28 fixed on 2022/05/13 11:13
linux-4.19 INFO: task hung in linkwatch_event 3 1831d 1945d 0/1 auto-closed as invalid on 2020/02/07 01:11
upstream INFO: task hung in linkwatch_event (3) net 1634 97d 691d 26/28 fixed on 2024/07/09 19:14
linux-4.14 INFO: task hung in linkwatch_event (3) 2 649d 650d 0/1 upstream: reported on 2023/01/03 10:49
android-49 INFO: task hung in linkwatch_event 13 1993d 2010d 0/3 auto-closed as invalid on 2019/10/25 08:50
linux-6.1 INFO: task hung in linkwatch_event (2) 32 32d 146d 0/3 upstream: reported on 2024/05/20 16:52
linux-6.1 INFO: task hung in linkwatch_event 2 435d 551d 0/3 auto-obsoleted due to no activity on 2023/11/14 00:59

Sample crash report:
INFO: task kworker/0:1:22 blocked for more than 140 seconds.
      Not tainted 4.14.91+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:1     D28656    22      2 0x80000000
Workqueue: events linkwatch_event
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3490
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 linkwatch_event+0xa/0x50 net/core/link_watch.c:236
 process_one_work+0x7c6/0x14e0 kernel/workqueue.c:2114
 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2248
 kthread+0x310/0x420 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402

Showing all locks held in the system:
3 locks held by kworker/0:1/22:
 #0:  ("events"){+.+.}, at: [<ffffffff86927d15>] process_one_work+0x6e5/0x14e0 kernel/workqueue.c:2085
 #1:  ((linkwatch_work).work){+.+.}, at: [<ffffffff86927d4b>] process_one_work+0x71b/0x14e0 kernel/workqueue.c:2089
 #2:  (rtnl_mutex){+.+.}, at: [<ffffffff87b5de1a>] linkwatch_event+0xa/0x50 net/core/link_watch.c:236
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff869ff97c>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
3 locks held by kworker/1:1/68:
 #0:  ("%s"("ipv6_addrconf")){+.+.}, at: [<ffffffff86927d15>] process_one_work+0x6e5/0x14e0 kernel/workqueue.c:2085
 #1:  ((addr_chk_work).work){+.+.}, at: [<ffffffff86927d4b>] process_one_work+0x71b/0x14e0 kernel/workqueue.c:2089
 #2:  (rtnl_mutex){+.+.}, at: [<ffffffff87eca22a>] addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4430
2 locks held by getty/1746:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff87536982>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:275
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff87531da7>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.91+ #1
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8804e402

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/01/01 13:28 android-4.14 7d2d5fc1acda 3d85f48c .config console log report syz C ci-android-414-kasan-gce-root
2019/11/16 11:34 android-4.14 460dc7c31cef cdac920b .config console log report ci-android-414-kasan-gce-root
2019/10/14 03:31 android-4.14 1d75f58e4e19 2f661ec4 .config console log report ci-android-414-kasan-gce-root
2019/04/21 13:41 android-4.14 fde41616bce4 b0e8efcb .config console log report ci-android-414-kasan-gce-root
2019/04/19 23:30 android-4.14 cec361536f1e b0e8efcb .config console log report ci-android-414-kasan-gce-root
2018/09/09 08:28 android-4.14 b859aa7d7a0c 6b5120a4 .config console log report ci-android-414-kasan-gce-root
2018/09/06 20:19 android-4.14 b859aa7d7a0c 0bb7a7eb .config console log report ci-android-414-kasan-gce-root
* Struck through repros no longer work on HEAD.