BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 260s! INFO: task kworker/u4:0:5 blocked for more than 140 seconds. Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 0: cpus=0 Not tainted 4.14.266-syzkaller #0 node=0 flags=0x0 nice=0 active=23/256 refcnt=24 in-flight: 8014:rtc_timer_do_work pending: macvlan_process_broadcast, macvlan_process_broadcast, linkwatch_event, defense_work_handler, macvlan_process_broadcast, defense_work_handler "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. , vmstat_shepherd, cache_reap, defense_work_handler, macvlan_process_broadcast kworker/u4:0 D , defense_work_handler, macvlan_process_broadcast, defense_work_handler, hci_cmd_timeout, hci_cmd_timeout 27600 5 2 0x80000000 , hci_cmd_timeout, hci_cmd_timeout, free_obj_work, push_to_pool, hci_cmd_timeout Workqueue: events_unbound fsnotify_connector_destroy_workfn , hci_cmd_timeout, switchdev_deferred_process_work workqueue events_unbound: flags=0x2 pwq 4: cpus=0-1 flags=0x4 nice=0 active=4/512 refcnt=7 in-flight: 33:fsnotify_mark_destroy_workfn fsnotify_mark_destroy_workfn, 5:fsnotify_connector_destroy_workfn fsnotify_connector_destroy_workfn workqueue events_power_efficient: flags=0x80 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256 refcnt=5 pending: fb_flashcursor, process_srcu, neigh_periodic_work, do_cache_clean Call Trace: workqueue mm_percpu_wq: flags=0x8 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue dm_bufio_cache: flags=0x8 context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: work_fn workqueue ipv6_addrconf: flags=0x40008 pwq 0: schedule+0x8d/0x1b0 kernel/sched/core.c:3431 cpus=0 node=0 flags=0x0 nice=0 active=1/1 refcnt=96 pending: addrconf_dad_work delayed: addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1724 , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work, addrconf_dad_work __synchronize_srcu+0x10a/0x1d0 kernel/rcu/srcutree.c:898 , addrconf_dad_work, addrconf_dad_work, addrconf_dad_work pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=260s workers=5 idle: 24 3 9212 3624 pool 4: cpus=0-1 flags=0x4 nice=0 hung=0s workers=7 idle: 2819 9346 2850 7112 22 fsnotify_connector_destroy_workfn+0x49/0xa0 fs/notify/mark.c:156 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: task kworker/u4:2:33 blocked for more than 140 seconds. Not tainted 4.14.266-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:2 D28872 33 2 0x80000000 Workqueue: events_unbound fsnotify_mark_destroy_workfn Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1724 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 __synchronize_srcu+0x10a/0x1d0 kernel/rcu/srcutree.c:898 fsnotify_mark_destroy_workfn+0xed/0x2e0 fs/notify/mark.c:757 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Showing all locks held in the system: 2 locks held by kworker/u4:0/5: #0: ("events_unbound"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: (connector_reaper_work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 2 locks held by kworker/u4:2/33: #0: ("events_unbound"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: ((reaper_work).work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 1 lock held by khungtaskd/1532: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by syz-executor.4/21927: #0: (&rtc->ops_lock){+.+.}, at: [] rtc_dev_ioctl+0xce/0x760 drivers/rtc/rtc-dev.c:219 1 lock held by syz-executor.4/21939: #0: (&rtc->ops_lock){+.+.}, at: [] rtc_dev_ioctl+0xce/0x760 drivers/rtc/rtc-dev.c:219 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1532 Comm: khungtaskd Not tainted 4.14.266-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+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 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+0x5b9/0xb40 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8014 Comm: kworker/0:3 Not tainted 4.14.266-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events rtc_timer_do_work task: ffff8880a16e03c0 task.stack: ffff8880b37a0000 RIP: 0010:trace_hardirqs_off_caller+0x97/0x2b0 kernel/locking/lockdep.c:2957 RSP: 0018:ffff8880b37a7b70 EFLAGS: 00000046 RAX: 0000000000000007 RBX: ffff8880a16e03c0 RCX: 1ffffffff127a3e4 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880a16e0c44 RBP: ffffffff87241776 R08: ffff8880a8f9daa0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a16e03c0 R13: ffff8880a8f9da48 R14: ffff8880a8f9dba0 R15: ffffffff84b0fa90 FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe06aa51028 CR3: 00000000a417b000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] _raw_spin_lock_irqsave+0x66/0xc0 kernel/locking/spinlock.c:160 rtc_handle_legacy_irq+0x28/0x180 drivers/rtc/interface.c:513 rtc_timer_do_work+0x1f7/0x5a0 drivers/rtc/interface.c:881 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 c5 01 00 00 41 8b b4 24 84 08 00 00 85 f6 0f 85 4c 01 00 00 <48> c7 c0 40 dd ec 8b 48 ba 00 00 00 00 00 fc ff df 48 89 c1 83 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 03 0f add (%rdi),%ecx 2: b6 14 mov $0x14,%dh 4: 02 48 89 add -0x77(%rax),%cl 7: f8 clc 8: 83 e0 07 and $0x7,%eax b: 83 c0 03 add $0x3,%eax e: 38 d0 cmp %dl,%al 10: 7c 08 jl 0x1a 12: 84 d2 test %dl,%dl 14: 0f 85 c5 01 00 00 jne 0x1df 1a: 41 8b b4 24 84 08 00 mov 0x884(%r12),%esi 21: 00 22: 85 f6 test %esi,%esi 24: 0f 85 4c 01 00 00 jne 0x176 * 2a: 48 c7 c0 40 dd ec 8b mov $0xffffffff8becdd40,%rax <-- trapping instruction 31: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx 38: fc ff df 3b: 48 89 c1 mov %rax,%rcx 3e: 83 .byte 0x83