IPVS: stopping backup sync thread 12493 ... INFO: task kworker/0:1:25 blocked for more than 120 seconds. Not tainted 4.9.99-g74fa0af4 #24 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:1 D26872 25 2 0x00000000 Workqueue: ipv6_addrconf addrconf_verify_work ffff8801d9bf9800 0000000000000000 ffff8801b6700a80 ffff8801cf380000 ffff8801db221b98 ffff8801d9427ae8 ffffffff839e377d ffff8801d9bfa0c8 ffff8801cf380000 ffff8801db221b80 00fffc0000000000 ffff8801db222468 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3557 [] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590 [] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621 [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 [] addrconf_verify_work+0xe/0x20 net/ipv6/addrconf.c:4366 [] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092 [] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Showing all locks held in the system: 3 locks held by kworker/0:1/25: #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] work_static include/linux/workqueue.h:186 [inline] #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("%s"("ipv6_addrconf")){.+.+..}, at: [] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085 #1: ((addr_chk_work).work){+.+...}, at: [] process_one_work+0x728/0x1500 kernel/workqueue.c:2089 #2: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 2 locks held by khungtaskd/519: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 1 lock held by rsyslogd/3675: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 2 locks held by getty/3771: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133 1 lock held by syz-executor4/12481: #0: (ipvs->sync_mutex){+.+.+.}, at: [] do_ip_vs_set_ctl+0x645/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2402 2 locks held by syz-executor4/12492: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 #1: (ipvs->sync_mutex){+.+.+.}, at: [] do_ip_vs_set_ctl+0x90d/0xbd0 net/netfilter/ipvs/ip_vs_ctl.c:2397 1 lock held by ipvs-b:92:0/12493: #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.99-g74fa0af4 #24 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8687d08 ffffffff81eb0f09 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810b7da0 ffff8801d8687d40 ffffffff81ebc207 0000000000000000 0000000000000000 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] 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 0xffffffff839f3286