INFO: task kworker/1:4:20079 blocked for more than 143 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:4 D26936 20079 2 0x80004000 Workqueue: events switchdev_deferred_process_work Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:74 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INFO: task kworker/1:7:21475 blocked for more than 144 seconds. Not tainted 5.5.0-rc4-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:7 D26632 21475 2 0x80004000 Workqueue: events linkwatch_event Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 linkwatch_event+0xf/0x70 net/core/link_watch.c:242 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 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: 3 locks held by kworker/u4:1/21: 5 locks held by kworker/u4:5/322: 1 lock held by khungtaskd/1103: #0: ffffffff899a5680 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/9155: #0: ffff888090c503a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9245: #0: ffff8880944d7090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000175b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9246: #0: ffff8880a20c4090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9247: #0: ffff8880a20c9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000179b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9248: #0: ffff8880a33ab090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000177b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9249: #0: ffff8880a8af4090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9250: #0: ffff8880a298b090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017272e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9251: #0: ffff8880a7ed6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900016fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 3 locks held by kworker/1:4/20079: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc90001917dc0 (deferred_process_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff8a4bbc80 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 3 locks held by kworker/1:6/21472: #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff888215506128 ((wq_completion)ipv6_addrconf){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc900061cfdc0 ((addr_chk_work).work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff8a4bbc80 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 3 locks held by kworker/1:7/21475: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc900060bfdc0 ((linkwatch_work).work){+.+.} , at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff8a4bbc80 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 1 lock held by udevd/23986: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1103 Comm: khungtaskd Not tainted 5.5.0-rc4-syzkaller #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+0x197/0x210 lib/dump_stack.c:118 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+0xb11/0x10c0 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: 322 Comm: kworker/u4:5 Not tainted 5.5.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:hlock_class kernel/locking/lockdep.c:163 [inline] RIP: 0010:__lock_acquire+0x19f4/0x4a00 kernel/locking/lockdep.c:3951 Code: ff 66 81 e3 ff 1f 0f b7 db be 08 00 00 00 48 89 d8 48 c1 f8 06 48 8d 3c c5 60 ed 2c 8b e8 14 f1 57 00 48 0f a3 1d fc 25 d2 09 <4c> 8b 95 70 ff ff ff 4c 8b 9d 30 ff ff ff 0f 83 18 07 00 00 48 69 RSP: 0018:ffffc90001f574d0 EFLAGS: 00000047 RAX: 0000000000000001 RBX: 00000000000000e9 RCX: ffffffff815ac75c RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8b2ced78 RBP: ffffc90001f575e8 R08: 1ffffffff1659daf R09: fffffbfff1659db0 R10: fffffbfff1659daf R11: ffffffff8b2ced7f R12: 00000000a2603fb1 R13: ffffffff8a79d090 R14: ffff8880a89bacd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000716158 CR3: 000000008bd5c000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 get_next_corpse net/netfilter/nf_conntrack_core.c:2001 [inline] nf_ct_iterate_cleanup+0x1d2/0x4e0 net/netfilter/nf_conntrack_core.c:2035 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2120 [inline] nf_ct_iterate_cleanup_net+0x133/0x190 net/netfilter/nf_conntrack_core.c:2105 masq_device_event+0xb5/0xe0 net/netfilter/nf_nat_masquerade.c:88 notifier_call_chain+0xc2/0x230 kernel/notifier.c:83 __raw_notifier_call_chain kernel/notifier.c:361 [inline] raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:368 call_netdevice_notifiers_info net/core/dev.c:1893 [inline] call_netdevice_notifiers_info+0xba/0x130 net/core/dev.c:1878 call_netdevice_notifiers_extack net/core/dev.c:1905 [inline] call_netdevice_notifiers net/core/dev.c:1919 [inline] dev_close_many+0x32a/0x6c0 net/core/dev.c:1544 rollback_registered_many+0x42e/0x10d0 net/core/dev.c:8721 unregister_netdevice_many.part.0+0x1b/0x1f0 net/core/dev.c:9907 unregister_netdevice_many net/core/dev.c:9906 [inline] default_device_exit_batch+0x360/0x420 net/core/dev.c:10380 ops_exit_list.isra.0+0x10c/0x160 net/core/net_namespace.c:175 cleanup_net+0x538/0xaf0 net/core/net_namespace.c:597 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352