RAX: ffffffffffffffda RBX: 00007fe86ad586d4 RCX: 0000000000454e79 RDX: 000000000000001f RSI: 0000000020000080 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000014 R13: 00000000000006af R14: 00000000006fc108 R15: 0000000000000004 INFO: task kworker/u4:5:5755 blocked for more than 120 seconds. Not tainted 4.16.0-rc6+ #288 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:5 D10512 5755 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3557 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 netdev_run_todo+0x60a/0x9f0 net/core/dev.c:8227 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:114 ip_tunnel_delete_nets+0x466/0x620 net/ipv4/ip_tunnel.c:1064 vti_exit_batch_net+0x22/0x30 net/ipv4/ip_vti.c:449 ops_exit_list.isra.6+0x100/0x150 net/core/net_namespace.c:154 cleanup_net+0x4d8/0xa90 net/core/net_namespace.c:522 process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 INFO: lockdep is turned off. NMI backtrace for cpu 0 CPU: 0 PID: 876 Comm: khungtaskd Not tainted 4.16.0-rc6+ #288 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 Kernel panic - not syncing: hung_task: blocked tasks CPU: 0 PID: 876 Comm: khungtaskd Not tainted 4.16.0-rc6+ #288 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 panic+0x1e4/0x41c kernel/panic.c:183 check_hung_task kernel/hung_task.c:133 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x91d/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds..