INFO: task kworker/u4:4:2553 blocked for more than 143 seconds. Not tainted 5.3.0+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:4 D24440 2553 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x94f/0x1e70 kernel/sched/core.c:4069 schedule+0xd9/0x260 kernel/sched/core.c:4136 rxrpc_destroy_all_calls+0x1fa/0x60e net/rxrpc/call_object.c:631 rxrpc_exit_net+0x1ba/0x310 net/rxrpc/net_ns.c:121 ops_exit_list.isra.0+0xaa/0x150 net/core/net_namespace.c:172 cleanup_net+0x4e2/0xa60 net/core/net_namespace.c:594 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 1 lock held by khungtaskd/1054: #0: ffffffff88faad40 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5337 3 locks held by kworker/u4:4/2553: #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: ffff8880a99abe68 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240 #1: ffff8880a1d47dc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244 #2: ffffffff89985a48 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xa60 net/core/net_namespace.c:556 1 lock held by rsyslogd/8537: 2 locks held by getty/8627: #0: ffff8880a9438910 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f312e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8628: #0: ffff8880933c06d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f2d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8629: #0: ffff8880a9439190 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f292e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8630: #0: ffff888098fc11d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8631: #0: ffff8880991f6e10 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f1d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8632: #0: ffff888098fc0950 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8633: #0: ffff88809c465590 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.3/11375: #0: ffffffff89985a48 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x25/0x270 net/core/dev.c:1806 1 lock held by syz-executor.3/11392: #0: ffffffff89985a48 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x25/0x270 net/core/dev.c:1806 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1054 Comm: khungtaskd Not tainted 5.3.0+ #0 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+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:205 [inline] watchdog+0x9d0/0xef0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60