INFO: task kworker/u4:0:7 blocked for more than 143 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:0 D25856 7 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 synchronize_rcu_expedited+0x431/0x5b0 kernel/rcu/tree_exp.h:775 synchronize_net+0x3b/0x60 net/core/dev.c:9263 rollback_registered_many+0x67b/0xfd0 net/core/dev.c:8187 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9308 unregister_netdevice_many+0x3b/0x50 net/core/dev.c:9307 ip_tunnel_delete_nets+0x41e/0x5f0 net/ipv4/ip_tunnel.c:1126 vti_exit_batch_net+0x23/0x30 net/ipv4/ip_vti.c:495 ops_exit_list.isra.0+0x105/0x160 net/core/net_namespace.c:156 cleanup_net+0x3fb/0x960 net/core/net_namespace.c:552 process_one_work+0x98e/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 INFO: task kworker/u4:1:21 blocked for more than 143 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:1 D24552 21 2 0x80000000 Workqueue: events_unbound fsnotify_connector_destroy_workfn Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_timeout+0x8ca/0xfd0 kernel/time/timer.c:1779 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __synchronize_srcu+0x197/0x250 kernel/rcu/srcutree.c:925 synchronize_srcu_expedited kernel/rcu/srcutree.c:950 [inline] synchronize_srcu+0x239/0x3e8 kernel/rcu/srcutree.c:1001 fsnotify_connector_destroy_workfn+0x4e/0xa0 fs/notify/mark.c:177 process_one_work+0x98e/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 INFO: task kworker/u4:8:13065 blocked for more than 144 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:8 D27232 13065 2 0x80000000 Workqueue: events_unbound fsnotify_mark_destroy_workfn Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_timeout+0x8ca/0xfd0 kernel/time/timer.c:1779 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __synchronize_srcu+0x197/0x250 kernel/rcu/srcutree.c:925 synchronize_srcu+0x2dc/0x3e8 kernel/rcu/srcutree.c:1003 fsnotify_mark_destroy_workfn+0x110/0x3b0 fs/notify/mark.c:827 process_one_work+0x98e/0x1790 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 INFO: task syz-executor.4:8844 blocked for more than 144 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29624 8844 8082 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 sock_do_ioctl+0x254/0x300 net/socket.c:1050 sock_ioctl+0x32b/0x610 net/socket.c:1168 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007fb3f1e6dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458c29 RDX: 0000000020000000 RSI: 0000001000008912 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb3f1e6e6d4 R13: 00000000004bfe5a R14: 00000000004d21b0 R15: 00000000ffffffff INFO: task syz-executor.5:8959 blocked for more than 144 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29960 8959 8084 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 sock_do_ioctl+0x254/0x300 net/socket.c:1050 sock_ioctl+0x32b/0x610 net/socket.c:1168 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007f790419fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458c29 RDX: 0000000020000000 RSI: 0000001000008912 RDI: 0000000000000003 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f79041a06d4 R13: 00000000004bfe5a R14: 00000000004d21b0 R15: 00000000ffffffff INFO: task syz-executor.1:8940 blocked for more than 145 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28648 8940 8072 0x80000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 gtp_net_exit+0x1cd/0x3a0 drivers/net/gtp.c:1317 ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:153 setup_net+0x400/0x740 net/core/net_namespace.c:332 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:438 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x440/0x980 kernel/fork.c:2549 __do_sys_unshare kernel/fork.c:2617 [inline] __se_sys_unshare kernel/fork.c:2615 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2615 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007fba61e96c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000458c29 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fba61e976d4 R13: 00000000004c7ccc R14: 00000000004ddf40 R15: 00000000ffffffff INFO: task syz-executor.3:8969 blocked for more than 145 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29624 8969 21176 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 sock_do_ioctl+0x254/0x300 net/socket.c:1050 sock_ioctl+0x32b/0x610 net/socket.c:1168 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007f279caa8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458c29 RDX: 0000000020000040 RSI: 0000001000008912 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f279caa96d4 R13: 00000000004bfe5a R14: 00000000004d21b0 R15: 00000000ffffffff INFO: task syz-executor.3:8988 blocked for more than 146 seconds. Not tainted 5.1.0-rc5+ #76 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28928 8988 21176 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x813/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3620 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 sock_do_ioctl+0x254/0x300 net/socket.c:1050 sock_ioctl+0x32b/0x610 net/socket.c:1168 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: Bad RIP value. RSP: 002b:00007f279ca87c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458c29 RDX: 0000000020000040 RSI: 0000001000008912 RDI: 0000000000000003 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f279ca886d4 R13: 00000000004bfe5a R14: 00000000004d21b0 R15: 00000000ffffffff Showing all locks held in the system: 5 locks held by kworker/u4:0/7: #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 0000000089fa10b9 ((wq_completion)netns){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2240 #1: 000000004ad950e1 (net_cleanup_work){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2244 #2: 000000005a43d30b (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0x960 net/core/net_namespace.c:519 #3: 00000000566a15c7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 #4: 0000000035c5f7c9 (rcu_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:285 [inline] #4: 0000000035c5f7c9 (rcu_state.exp_mutex){+.+.}, at: synchronize_rcu_expedited+0x4ab/0x5b0 kernel/rcu/tree_exp.h:758 2 locks held by kworker/u4:1/21: #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2240 #1: 0000000000fb89b6 (connector_reaper_work){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2244 1 lock held by khungtaskd/1042: #0: 000000002ffe52eb (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5056 1 lock held by rsyslogd/7908: #0: 00000000e4cc29d3 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8030: #0: 00000000c3cec34a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000042c4b2af (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8031: #0: 000000007bca5fcd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000083d75c6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8032: #0: 000000007a2cc72d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000b959e1d6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8033: #0: 00000000112a6ec4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000005901d6df (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8034: #0: 00000000d069bc83 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000cc33f73b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8035: #0: 00000000c5515d2e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000bbdaab6c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/8036: #0: 000000006a980dc8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000da579901 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 3 locks held by kworker/1:4/8120: 1 lock held by syz-executor.4/14590: #0: 0000000035c5f7c9 (rcu_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:317 [inline] #0: 0000000035c5f7c9 (rcu_state.exp_mutex){+.+.}, at: synchronize_rcu_expedited+0x26f/0x5b0 kernel/rcu/tree_exp.h:758 2 locks held by kworker/u4:8/13065: #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 000000000997dc4e ((wq_completion)events_unbound){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2240 #1: 00000000f97479b0 ((reaper_work).work){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2244 1 lock held by syz-executor.4/8844: #0: 00000000566a15c7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 1 lock held by syz-executor.5/8959: #0: 00000000566a15c7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 2 locks held by syz-executor.1/8940: #0: 000000005a43d30b (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1c0/0x340 net/core/net_namespace.c:434 #1: 00000000566a15c7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 1 lock held by syz-executor.3/8969: #0: 00000000566a15c7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 1 lock held by syz-executor.3/8988: #0: 00000000566a15c7 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:76 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1042 Comm: khungtaskd Not tainted 5.1.0-rc5+ #76 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: