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INFO: task hung in stop_sync_thread

Status: closed as invalid on 2018/03/27 11:14
First crash: 2216d, last: 2216d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in stop_sync_thread (2) lvs C 9 2197d 2214d 5/26 fixed on 2018/05/08 18:30
android-44 INFO: task hung in stop_sync_thread syz 12 2180d 1833d 0/2 public: reported syz repro on 2019/04/14 00:02
android-49 INFO: task hung in stop_sync_thread (2) 12 2063d 2213d 0/3 auto-closed as invalid on 2019/02/23 02:19
upstream INFO: task hung in stop_sync_thread lvs C 2 2215d 2216d 0/26 closed as invalid on 2018/03/27 11:14

Sample crash report:
IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0
IPVS: stopping backup sync thread 9976 ...
INFO: task syz-executor6:9973 blocked for more than 120 seconds.
      Not tainted 4.9.90-gdd1e37e #66
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D27888  9973   3875 0x00000004
 ffff8801d6a29800 ffff8801d80439c0 ffff8801c34b3480 ffff8801d81cb000
 ffff8801db221b98 ffff8801d305f7a0 ffffffff838a75cb ffffed003ad4541f
 ffff8801d6a2a0fa 00ffffff00000000 ffff8801db222468 ffff8801db222490
Call Trace:
 [<ffffffff838a8b6f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3551
 [<ffffffff838b4b2c>] schedule_timeout+0x56c/0x10b0 kernel/time/timer.c:1768
 [<ffffffff838abcae>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff838abcae>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff838abcae>] wait_for_common kernel/sched/completion.c:101 [inline]
 [<ffffffff838abcae>] wait_for_completion+0x20e/0x2e0 kernel/sched/completion.c:122
 [<ffffffff8119cc46>] kthread_stop+0xa6/0x5d0 kernel/kthread.c:513
 [<ffffffff831c5239>] stop_sync_thread+0x3d9/0x740 net/netfilter/ipvs/ip_vs_sync.c:1998
 [<ffffffff831ad9d1>] do_ip_vs_set_ctl+0x251/0xc00 net/netfilter/ipvs/ip_vs_ctl.c:2403
 [<ffffffff830a53e7>] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline]
 [<ffffffff830a53e7>] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:114
 [<ffffffff83215ba7>] ip_setsockopt+0x97/0xa0 net/ipv4/ip_sockglue.c:1247
 [<ffffffff832c37a5>] udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2088
 [<ffffffff82ee1295>] sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2706
 [<ffffffff82ede250>] SYSC_setsockopt net/socket.c:1772 [inline]
 [<ffffffff82ede250>] SyS_setsockopt+0x160/0x250 net/socket.c:1751
 [<ffffffff81006504>] do_syscall_64+0x1a4/0x490 arch/x86/entry/common.c:282
 [<ffffffff838b8493>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
3 locks held by kworker/1:0/18:
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118af42>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118af42>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118af42>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("%s"("ipv6_addrconf")){.+.+..}, at: [<ffffffff8118af42>] process_one_work+0x6f2/0x1610 kernel/workqueue.c:2085
 #1:  ((addr_chk_work).work){+.+...}, at: [<ffffffff8118af7c>] process_one_work+0x72c/0x1610 kernel/workqueue.c:2089
 #2:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f79737>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
2 locks held by khungtaskd/515:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81372185>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81372185>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81236c50>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3652:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d2f5f>] __fdget_pos+0x9f/0xc0 fs/file.c:781
2 locks held by getty/3781:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838b66a2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8200a6a4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor6/9973:
 #0:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff831ad9c0>] do_ip_vs_set_ctl+0x240/0xc00 net/netfilter/ipvs/ip_vs_ctl.c:2402
2 locks held by syz-executor6/9974:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f79737>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #1:  (ipvs->sync_mutex){+.+.+.}, at: [<ffffffff831ae067>] do_ip_vs_set_ctl+0x8e7/0xc00 net/netfilter/ipvs/ip_vs_ctl.c:2397
1 lock held by ipvs-b:8:0/9976:
 #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff82f79737>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70

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

NMI backtrace for cpu 0
CPU: 0 PID: 515 Comm: khungtaskd Not tainted 4.9.90-gdd1e37e #66
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8687d00 ffffffff81d94ee9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bb920 ffff8801d8687d38
 ffffffff81da000d 0000000000000000 0000000000000000 ffff8801d4670418
Call Trace:
 [<ffffffff81d94ee9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d94ee9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da000d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81da0147>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bba14>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81372750>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81372750>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81372750>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81372750>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119bf4d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838b865c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff838b7116

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/03/26 17:11 https://android.googlesource.com/kernel/common android-4.9 dd1e37e64645 0ca7878b .config console log report ci-android-49-kasan-gce
* Struck through repros no longer work on HEAD.