INFO: task kworker/u4:2:14637 blocked for more than 143 seconds. Not tainted 5.4.0-rc2+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:2 D25416 14637 2 0x80004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x74b/0xb80 kernel/sched/core.c:4069 schedule+0x131/0x1e0 kernel/sched/core.c:4136 rxrpc_destroy_all_calls+0x16a/0x530 net/rxrpc/call_object.c:631 rxrpc_exit_net+0x61/0xb0 net/rxrpc/net_ns.c:121 ops_exit_list net/core/net_namespace.c:172 [inline] cleanup_net+0x69a/0xaa0 net/core/net_namespace.c:594 process_one_work+0x7ef/0x10e0 kernel/workqueue.c:2269 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 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/1064: #0: ffffffff888d3ec0 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 2 locks held by getty/7863: #0: ffff8880a7b78090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f212e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7864: #0: ffff8880a99ee090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7865: #0: ffff8880a37d0090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f292e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7866: #0: ffff8880a30a7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f052e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7867: #0: ffff88809e961090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7868: #0: ffff8880a7b66090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f252e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7869: #0: ffff8880a767d090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005ef12e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:2/14637: #0: ffff88821b6bb928 ((wq_completion)netns){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff88821b6bb928 ((wq_completion)netns){+.+.}, at: process_one_work+0x75d/0x10e0 kernel/workqueue.c:2242 #1: ffff888052637d78 (net_cleanup_work){+.+.}, at: process_one_work+0x79f/0x10e0 kernel/workqueue.c:2244 #2: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa5/0xaa0 net/core/net_namespace.c:556 1 lock held by syz-executor.1/23753: #0: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x32/0x5f0 net/core/dev.c:1644 1 lock held by syz-executor.1/23754: #0: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x32/0x5f0 net/core/dev.c:1644 1 lock held by syz-executor.1/23755: #0: ffffffff88b00a68 (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x32/0x5f0 net/core/dev.c:1644 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1064 Comm: khungtaskd Not tainted 5.4.0-rc2+ #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+0x1d8/0x2f8 lib/dump_stack.c:113 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace+0x17/0x20 include/linux/nmi.h:146 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xbb9/0xbd0 kernel/hung_task.c:289 kthread+0x332/0x350 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: 8006 Comm: kworker/u4:6 Not tainted 5.4.0-rc2+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:debug_lockdep_rcu_enabled+0x60/0xe0 kernel/rcu/update.c:252 Code: be 88 48 c1 e8 03 42 8a 04 38 84 c0 75 59 83 3d 15 86 5e 07 00 74 28 65 4c 8b 34 25 c0 fd 01 00 49 81 c6 94 08 00 00 4c 89 f0 <48> c1 e8 03 42 8a 04 38 84 c0 75 59 31 db 41 83 3e 00 0f 94 c3 89 RSP: 0018:ffff88806e8dfbf8 EFLAGS: 00000082 RAX: ffff88808b18ec54 RBX: 0000000000000000 RCX: ffffffff81586d6b RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff88be3d60 RBP: ffff88806e8dfc10 R08: dffffc0000000000 R09: fffffbfff117c7ad R10: fffffbfff117c7ad R11: 0000000000000000 R12: dffffc0000000000 R13: ffffffff81580bb0 R14: ffff88808b18ec54 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c42419e590 CR3: 00000000a0cb4000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire+0x159/0x1d0 include/trace/events/lock.h:13 lock_acquire+0x125/0x250 kernel/locking/lockdep.c:4486 process_one_work+0x7c2/0x10e0 kernel/workqueue.c:2245 worker_thread+0xc01/0x1630 kernel/workqueue.c:2415 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352