INFO: task syz-executor.0:19635 blocked for more than 143 seconds. Not tainted 5.6.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D27664 19635 7039 0x00004004 Call Trace: context_switch kernel/sched/core.c:3378 [inline] __schedule+0x805/0xc90 kernel/sched/core.c:4094 schedule+0x188/0x220 kernel/sched/core.c:4168 rwsem_down_write_slowpath+0x7d0/0xd60 kernel/locking/rwsem.c:1235 calibrate_delay+0x1181/0x125a init/calibrate.c:306 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x125/0x130 kernel/locking/rwsem.c:1532 register_netdevice_notifier+0x30/0x8c0 net/core/dev.c:1729 memset+0x1f/0x40 mm/kasan/common.c:108 bcm_init+0x11e/0x160 net/can/bcm.c:1451 bcm_rx_thr_handler+0x920/0x920 net/can/bcm.c:448 can_create+0x247/0x480 net/can/af_can.c:168 __sock_create+0x5c9/0x8d0 net/socket.c:1433 sock_create net/socket.c:1484 [inline] __sys_socket+0xde/0x2d0 net/socket.c:1526 __do_sys_socket net/socket.c:1535 [inline] __se_sys_socket net/socket.c:1533 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1533 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 INFO: task syz-executor.0:19639 blocked for more than 143 seconds. Not tainted 5.6.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29584 19639 7039 0x00004004 Call Trace: context_switch kernel/sched/core.c:3378 [inline] __schedule+0x805/0xc90 kernel/sched/core.c:4094 schedule+0x188/0x220 kernel/sched/core.c:4168 rwsem_down_write_slowpath+0x7d0/0xd60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x125/0x130 kernel/locking/rwsem.c:1532 register_netdevice_notifier+0x30/0x8c0 net/core/dev.c:1729 memset+0x1f/0x40 mm/kasan/common.c:108 bcm_init+0x11e/0x160 net/can/bcm.c:1451 bcm_rx_thr_handler+0x920/0x920 net/can/bcm.c:448 can_create+0x247/0x480 net/can/af_can.c:168 __sock_create+0x5c9/0x8d0 net/socket.c:1433 sock_create net/socket.c:1484 [inline] __sys_socket+0xde/0x2d0 net/socket.c:1526 __do_sys_socket net/socket.c:1535 [inline] __se_sys_socket net/socket.c:1533 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1533 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Showing all locks held in the system: 1 lock held by khungtaskd/1135: #0: ffffffff892e69d0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 lib/xarray.c:75 1 lock held by in:imklog/6707: #0: ffff88809437de30 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x25d/0x2f0 fs/file.c:826 2 locks held by rs:main Q:Reg/6708: #0: ffff8880ae9374d8 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1257 [inline] #0: ffff8880ae9374d8 (&rq->lock){-.-.}-{2:2}, at: __schedule+0xda/0xc90 kernel/sched/core.c:4040 #1: ffff8880ae922d48 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x215/0x5d0 kernel/sched/psi.c:817 3 locks held by kworker/u4:6/8636: #0: ffff8880a9b79938 ((wq_completion)netns){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline] #0: ffff8880a9b79938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2239 #1: ffffc900023afd80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2241 #2: ffffffff895a71f0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xac/0xb80 net/core/net_namespace.c:565 1 lock held by syz-executor.0/19635: #0: ffffffff895a71f0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x30/0x8c0 net/core/dev.c:1729 1 lock held by syz-executor.0/19639: #0: ffffffff895a71f0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x30/0x8c0 net/core/dev.c:1729 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1135 Comm: khungtaskd Not tainted 5.6.0-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+0x1e9/0x30e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 arch_trigger_cpumask_backtrace+0x10/0x10 arch/x86/kernel/apic/hw_nmi.c:38 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd2a/0xd40 kernel/hung_task.c:289 kthread+0x353/0x380 kernel/kthread.c:268 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8636 Comm: kworker/u4:6 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:5212 [inline] RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:5251 [inline] RIP: 0010:zap_class+0x35a/0x9c0 kernel/locking/lockdep.c:5291 Code: 49 8b 45 00 4c 8d 68 f8 48 85 c0 4c 0f 44 e8 4d 85 ed 74 8c 4c 89 ee 48 c1 ee 03 8a 04 0e 84 c0 0f 85 4d 02 00 00 45 8b 75 00 <44> 89 f3 c1 eb 02 83 e3 3f 0f 84 0a 02 00 00 49 c1 ee 08 45 89 f4 RSP: 0018:ffffc900023afa80 EFLAGS: 00000046 RAX: ffffffff8ab89d00 RBX: 0000000000000006 RCX: dffffc0000000000 RDX: 0000000000000cfa RSI: 1ffffffff15713a2 RDI: ffffffff8b133a08 RBP: ffffffff8aeac26c R08: dffffc0000000000 R09: fffffbfff1626742 R10: fffffbfff1626742 R11: 0000000000000000 R12: 000000000001550e R13: ffffffff8ab89d10 R14: 0000000001268314 R15: 000000000001550e FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd28e01f000 CR3: 0000000094781000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lockdep_free_key_range kernel/locking/lockdep.c:5413 [inline] lockdep_unregister_key+0x3a0/0x790 kernel/locking/lockdep.c:5603 netdev_unregister_lockdep_key net/core/dev.c:9257 [inline] free_netdev+0x263/0x380 net/core/dev.c:9915 netdev_run_todo+0xaca/0xcb0 net/core/dev.c:9657 __list_del_entry include/linux/list.h:135 [inline] list_del include/linux/list.h:146 [inline] unregister_netdevice_many+0x1a2/0x260 net/core/dev.c:9989 ip_tunnel_delete_nets+0x2ea/0x310 net/ipv4/ip_tunnel.c:1110 ipgre_init_net+0x30/0x30 net/ipv4/ip_gre.c:992 ops_exit_list net/core/net_namespace.c:189 [inline] cleanup_net+0x78c/0xb80 net/core/net_namespace.c:603 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2266 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2412 kthread+0x353/0x380 kernel/kthread.c:268 rcu_lock_release+0x20/0x20 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352