INFO: task kworker/0:3:7348 blocked for more than 140 seconds. Not tainted 4.14.178-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:3 D27152 7348 2 0x80000000 Workqueue: events linkwatch_event Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 linkwatch_event+0xa/0x50 net/core/link_watch.c:236 process_one_work+0x813/0x1540 kernel/workqueue.c:2116 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: task syz-executor.5:8681 blocked for more than 140 seconds. Not tainted 4.14.178-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D26336 8681 6349 0x80000002 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 kobject_uevent_env+0x5a4/0xc50 lib/kobject_uevent.c:459 kobject_cleanup lib/kobject.c:633 [inline] kobject_release lib/kobject.c:675 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put+0x178/0x1f0 lib/kobject.c:692 net_rx_queue_update_kobjects+0x2df/0x3e0 net/core/net-sysfs.c:967 remove_queue_kobjects net/core/net-sysfs.c:1431 [inline] netdev_unregister_kobject+0x138/0x1d0 net/core/net-sysfs.c:1570 rollback_registered_many+0x620/0xa70 net/core/dev.c:7230 rollback_registered+0xd6/0x180 net/core/dev.c:7248 unregister_netdevice_queue net/core/dev.c:8260 [inline] unregister_netdevice_queue+0x1a1/0x220 net/core/dev.c:8253 unregister_netdevice include/linux/netdevice.h:2442 [inline] __tun_detach+0xa8d/0xcf0 drivers/net/tun.c:576 tun_detach drivers/net/tun.c:586 [inline] tun_chr_close+0x41/0x60 drivers/net/tun.c:2671 __fput+0x25f/0x790 fs/file_table.c:210 task_work_run+0x113/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9f2/0x2b00 kernel/exit.c:858 do_group_exit+0x100/0x310 kernel/exit.c:955 get_signal+0x385/0x1ca0 kernel/signal.c:2423 do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814 exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c829 RSP: 002b:00007ffa20debcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000078c0e8 RCX: 000000000045c829 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000078c0e8 RBP: 000000000078c0e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078c0ec R13: 00007ffe28d04caf R14: 00007ffa20dec9c0 R15: 000000000078c0ec Showing all locks held in the system: 1 lock held by khungtaskd/1015: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 3 locks held by kworker/1:2/2864: #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("%s"("ipv6_addrconf")){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: ((addr_chk_work).work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (rtnl_mutex){+.+.}, at: [] addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4412 3 locks held by kworker/0:3/7348: #0: ("events"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("events"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("events"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("events"){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: ((linkwatch_work).work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (rtnl_mutex){+.+.}, at: [] linkwatch_event+0xa/0x50 net/core/link_watch.c:236 2 locks held by syz-executor.5/8681: #0: (rtnl_mutex){+.+.}, at: [] tun_detach drivers/net/tun.c:585 [inline] #0: (rtnl_mutex){+.+.}, at: [] tun_chr_close+0x34/0x60 drivers/net/tun.c:2671 #1: (uevent_sock_mutex){+.+.}, at: [] kobject_uevent_env+0x5a4/0xc50 lib/kobject_uevent.c:459 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1015 Comm: khungtaskd Not tainted 4.14.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 11527 Comm: syz-executor.1 Not tainted 4.14.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888054714680 task.stack: ffff88804ec30000 RIP: 0033:0x401c42 RSP: 002b:00007f65c53e93d0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 000000000000000b RCX: 0000000000416687 RDX: 00007f65c53e94c0 RSI: 0000000024a918f0 RDI: 00000000004c139a RBP: 000000000078bf00 R08: 00007f65c53e9a70 R09: 000000000078bf00 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000bf1 R14: 00000000004ce15b R15: 00007f65c53ea6d4 FS: 00007f65c53ea700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000024a918f0 CR3: 00000000960c5000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400