BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 248s! Showing busy workqueues and worker pools: INFO: task kworker/u4:0:5 blocked for more than 140 seconds. workqueue events: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=14/256 refcnt=15 Not tainted 4.14.215-syzkaller #0 in-flight: 24:rtc_timer_do_work pending: defense_work_handler, macvlan_process_broadcast, macvlan_process_broadcast, macvlan_process_broadcast, macvlan_process_broadcast, macvlan_process_broadcast, macvlan_process_broadcast, vmstat_shepherd, cache_reap, defense_work_handler, hci_cmd_timeout, free_obj_work, push_to_pool "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. workqueue events_long: flags=0x0 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: gc_worker workqueue events_unbound: flags=0x2 pwq 4: cpus=0-1 flags=0x4 nice=0 active=4/512 refcnt=7 in-flight: 5:fsnotify_mark_destroy_workfn fsnotify_mark_destroy_workfn, 31:fsnotify_connector_destroy_workfn fsnotify_connector_destroy_workfn workqueue events_freezable: flags=0x4 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: update_balloon_stats_func workqueue events_power_efficient: flags=0x80 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=4/256 refcnt=5 pending: do_cache_clean, process_srcu, neigh_periodic_work, neigh_periodic_work 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 ipv6_addrconf: flags=0x40008 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1 refcnt=100 kworker/u4:0 D 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, 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 27640 5 2 0x80000000 , 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 Workqueue: events_unbound fsnotify_mark_destroy_workfn , 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 pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=248s workers=5 idle: 3 3624 9048 8967 pool 4: cpus=0-1 flags=0x4 nice=0 hung=0s workers=9 idle: 22 9380 9355 273 1128 9282 9370 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 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:2116 worker_thread+0x5cc/0xff0 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 kworker/u4:2:31 blocked for more than 140 seconds. Not tainted 4.14.215-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:2 D25112 31 2 0x80000000 Workqueue: events_unbound fsnotify_connector_destroy_workfn Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 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_connector_destroy_workfn+0x49/0xa0 fs/notify/mark.c:156 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 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:2087 #1: ((reaper_work).work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 2 locks held by kworker/u4:2/31: #0: ("events_unbound"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087 #1: (connector_reaper_work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 1 lock held by khungtaskd/1526: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/7737: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 1 lock held by syz-executor.4/7998: #0: (&rq->lock){-.-.}, at: [] rq_lock kernel/sched/sched.h:1741 [inline] #0: (&rq->lock){-.-.}, at: [] __schedule+0x1df/0x1de0 kernel/sched/core.c:3321 1 lock held by syz-executor.4/25878: #0: (&rtc->ops_lock){+.+.}, at: [] rtc_dev_ioctl+0xce/0x760 drivers/rtc/rtc-dev.c:219 1 lock held by syz-executor.4/25889: #0: (&rtc->ops_lock){+.+.}, at: [] rtc_dev_ioctl+0xce/0x760 drivers/rtc/rtc-dev.c:219 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1526 Comm: khungtaskd Not tainted 4.14.215-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+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f 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: 9380 Comm: kworker/u4:8 Not tainted 4.14.215-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker task: ffff8880a1b6a2c0 task.stack: ffff88809f9b8000 RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline] RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:417 [inline] RIP: 0010:batadv_nc_worker+0x151/0xc50 net/batman-adv/network-coding.c:726 RSP: 0018:ffff88809f9bfcd8 EFLAGS: 00000246 RAX: 1ffff11013ce111e RBX: ffff88809e7088f0 RCX: 1ffffffff11981ac RDX: 0000000000000000 RSI: ffffffff87ccd700 RDI: ffff8880ba422a4c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000020012 R10: ffff8880a1b6ab98 R11: ffff8880a1b6a2c0 R12: dffffc0000000000 R13: ffff8880a0301400 R14: ffff88813fe1a8c0 R15: ffff8880a51b5800 FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560ae8f78f68 CR3: 00000000ac3de000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 3f 3f fa 5a 85 c0 74 12 e8 3d 9b 4e fa 80 3d 4d 43 ea 02 00 0f 84 b8 06 00 00 e8 2b 9b 4e fa 48 89 d8 48 c1 e8 03 42 80 3c 20 00 <0f> 85 bb 0a 00 00 48 8b 2b 48 85 ed 0f 84 fd 03 00 00 e8 08 9b