INFO: task kworker/0:2:20313 blocked for more than 159 seconds. Not tainted 5.5.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:2 D26472 20313 2 0x80004000 Workqueue: events linkwatch_event Call Trace: context_switch kernel/sched/core.c:3386 [inline] __schedule+0x87f/0xcd0 kernel/sched/core.c:4082 schedule+0x188/0x210 kernel/sched/core.c:4156 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215 __mutex_lock_common+0x11f1/0x2f30 kernel/locking/mutex.c:1033 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 linkwatch_event+0xe/0x60 net/core/link_watch.c:242 process_one_work+0x7f5/0x10f0 kernel/workqueue.c:2264 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 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: 4 locks held by kworker/u4:2/35: #0: ffff88821bb8e528 ((wq_completion)netns){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff88821bb8e528 ((wq_completion)netns){+.+.}, at: process_one_work+0x763/0x10f0 kernel/workqueue.c:2237 #1: ffffc90000eb7d78 (net_cleanup_work){+.+.}, at: process_one_work+0x7a5/0x10f0 kernel/workqueue.c:2239 #2: ffffffff895882e8 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa5/0xb80 net/core/net_namespace.c:551 #3: ffffffff89589f20 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 1 lock held by khungtaskd/1133: #0: ffffffff892d9588 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 1 lock held by udevd/4358: 1 lock held by rsyslogd/8683: 2 locks held by getty/8773: #0: ffff88809f7a9090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000198b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8774: #0: ffff88809897a090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8775: #0: ffff88808c2c9090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc90001a0b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8776: #0: ffff8880a020d090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8777: #0: ffff8880a6bd0090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019832e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8778: #0: ffff88809f1be090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8779: #0: ffff8880a64af090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019632e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 3 locks held by kworker/0:2/20313: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x763/0x10f0 kernel/workqueue.c:2237 #1: ffffc9000880fd78 ((linkwatch_work).work){+.+.}, at: process_one_work+0x7a5/0x10f0 kernel/workqueue.c:2239 #2: ffffffff89589f20 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 3 locks held by kworker/0:3/11849: #0: ffff888214c28528 ((wq_completion)ipv6_addrconf){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff888214c28528 ((wq_completion)ipv6_addrconf){+.+.}, at: process_one_work+0x763/0x10f0 kernel/workqueue.c:2237 #1: ffffc9000dabfd78 ((addr_chk_work).work){+.+.}, at: process_one_work+0x7a5/0x10f0 kernel/workqueue.c:2239 #2: ffffffff89589f20 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 3 locks held by kworker/1:3/15938: #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: process_one_work+0x763/0x10f0 kernel/workqueue.c:2237 #1: ffffc90002f1fd78 (deferred_process_work){+.+.}, at: process_one_work+0x7a5/0x10f0 kernel/workqueue.c:2239 #2: ffffffff89589f20 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72 1 lock held by syz-executor.1/32332: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1133 Comm: khungtaskd Not tainted 5.5.0-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+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaa/0x190 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x16f/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+0xd40/0xd60 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: 32305 Comm: kworker/0:0 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_power_efficient gc_worker RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:2860 [inline] RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:2880 [inline] RIP: 0010:validate_chain+0x15f/0x7be0 kernel/locking/lockdep.c:2935 Code: 6b 18 4c 89 e8 48 c1 e8 03 80 3c 10 00 74 12 4c 89 ef e8 d4 75 57 00 48 ba 00 00 00 00 00 fc ff df 49 8b 45 00 4c 39 f0 74 25 <48> 83 c3 08 48 89 d8 48 c1 e8 03 80 3c 10 00 74 b0 48 89 df e8 a8 RSP: 0018:ffffc900014978e0 EFLAGS: 00000087 RAX: 0065890adc01a80f RBX: ffffffff89a20f10 RCX: ffffffff815c5305 RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff8a02a898 RBP: ffffc90001497ae0 R08: dffffc0000000000 R09: fffffbfff1405514 R10: fffffbfff1405514 R11: 0000000000000000 R12: ffff8880a3028978 R13: ffffffff89a20f28 R14: 2915ccb8db08a731 R15: ffff8880a30280c0 FS: 0000000000000000(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000e77a80 CR3: 00000000a95e9000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: __lock_acquire+0xc5a/0x1bc0 kernel/locking/lockdep.c:3954 lock_acquire+0x154/0x250 kernel/locking/lockdep.c:4484 process_one_work+0x7a1/0x10f0 kernel/workqueue.c:2239 worker_thread+0xbbc/0x1630 kernel/workqueue.c:2410 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352