INFO: task kworker/u4:5:9240 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/u4:5 D23048 9240 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x828/0x1c80 kernel/sched/core.c:4065 schedule+0xd9/0x260 kernel/sched/core.c:4132 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: 2 locks held by kworker/u4:1/21: #0: ffff8880ae934818 (&rq->lock){-.-.}, at: newidle_balance+0xa30/0xe90 kernel/sched/fair.c:9840 #1: ffffffff88fab300 (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:5848 1 lock held by khungtaskd/1063: #0: ffffffff88fab300 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5337 1 lock held by rsyslogd/9057: 2 locks held by getty/9179: #0: ffff8880a92497d0 (&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/9180: #0: ffff88809062a650 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f492e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9181: #0: ffff8880a2224510 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f552e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9182: #0: ffff8880a32ae210 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f4d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9183: #0: ffff88809062aed0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f452e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9184: #0: ffff8880a2231650 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f512e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9185: #0: ffff88808dcbad50 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f252e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:5/9240: #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: ffff88821bac1428 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240 #1: ffff88806a587dc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244 #2: ffffffff89993788 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xa60 net/core/net_namespace.c:556 1 lock held by syz-executor.1/27170: #0: ffffffff89993788 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1644 1 lock held by syz-executor.1/27177: #0: ffffffff89993788 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1644 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1063 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 CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__local_bh_disable_ip+0xef/0x1b0 kernel/softirq.c:129 Code: ad 07 00 0f 84 9c 00 00 00 4c 89 ef 57 9d 0f 1f 44 00 00 65 8b 05 99 39 bc 7e 25 ff ff ff 7f 39 d8 74 11 5b 41 5c 41 5d 5d c3 <4c> 89 e7 e8 59 aa 13 00 eb a8 48 8b 5d 08 65 4c 8b 24 25 40 fe 01 RSP: 0018:ffff8880a9a5fc20 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000201 RCX: ffffffff872a7d83 RDX: 0000000080000000 RSI: 0000000000000201 RDI: ffffffff872a7bc8 RBP: ffff8880a9a5fc38 R08: ffff8880a9a52580 R09: fffffbfff14efb43 R10: fffffbfff14efb42 R11: ffffffff8a77da17 R12: ffffffff872a7bc8 R13: 0000000000000282 R14: ffffffff872a8820 R15: 0000000000000032 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 000000009a62f000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_bh include/linux/spinlock_api_smp.h:134 [inline] _raw_spin_lock_bh+0x17/0x50 kernel/locking/spinlock.c:175 spin_lock_bh include/linux/spinlock.h:343 [inline] batadv_nc_purge_paths+0xd8/0x370 net/batman-adv/network-coding.c:441 batadv_nc_worker+0x2cf/0x760 net/batman-adv/network-coding.c:721 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