BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 258s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=27/256 refcnt=28 in-flight: 3079:rtc_timer_do_work pending: defense_work_handler, defense_work_handler, defense_work_handler, destroy_super_work, cache_reap, free_obj_work, destroy_super_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, nfc_urelease_event_work, wait_rcu_exp_gp workqueue events_long: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=2/256 refcnt=3 pending: br_fdb_cleanup, br_fdb_cleanup 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: 25605:fsnotify_mark_destroy_workfn fsnotify_mark_destroy_workfn, 24083:fsnotify_connector_destroy_workfn fsnotify_connector_destroy_workfn workqueue events_freezable: flags=0x4 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: update_balloon_stats_func workqueue events_power_efficient: flags=0x80 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=3/256 refcnt=4 pending: process_srcu, fb_flashcursor, neigh_periodic_work pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 in-flight: 32082:sync_cmos_clock workqueue mm_percpu_wq: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue dm_bufio_cache: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: work_fn workqueue bat_events: flags=0xe000a pwq 4: cpus=0-1 flags=0x4 nice=0 active=1/1 refcnt=13 pending: batadv_iv_send_outstanding_bat_ogm_packet delayed: batadv_iv_send_outstanding_bat_ogm_packet, batadv_tt_purge, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_mcast_mla_update pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=0s workers=3 idle: 18473 3228 pool 2: cpus=1 node=0 flags=0x0 nice=0 hung=259s workers=3 idle: 25378 18790 pool 4: cpus=0-1 flags=0x4 nice=0 hung=0s workers=4 idle: 2724 6447 INFO: task syz-executor.0:7993 blocked for more than 140 seconds. Not tainted 4.14.281-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D25632 7993 1 0x80000006 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 exp_funnel_lock kernel/rcu/tree_exp.h:295 [inline] _synchronize_rcu_expedited+0x5f6/0x770 kernel/rcu/tree_exp.h:596 synchronize_rcu+0x98/0x130 kernel/rcu/tree_plugin.h:762 namespace_unlock fs/namespace.c:1448 [inline] drop_collected_mounts+0x147/0x160 fs/namespace.c:1888 put_mnt_ns fs/namespace.c:3348 [inline] put_mnt_ns+0x42/0x60 fs/namespace.c:3344 free_nsproxy+0x40/0x1f0 kernel/nsproxy.c:176 switch_task_namespaces+0x8f/0xb0 kernel/nsproxy.c:229 do_exit+0xa3f/0x2850 kernel/exit.c:867 do_group_exit+0x100/0x2e0 kernel/exit.c:965 get_signal+0x38d/0x1ca0 kernel/signal.c:2412 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:792 exit_to_usermode_loop+0x160/0x200 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+0x46/0xbb RIP: 0033:0x7f9449ed85a7 RSP: 002b:00007fff2ed1a500 EFLAGS: 00000293 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 0000000000003d8b RCX: 00007f9449ed85a7 RDX: 0000000040000000 RSI: 00007fff2ed1a58c RDI: 00000000ffffffff RBP: 00007fff2ed1a58c R08: 0000000000000000 R09: 00007f9449fc0640 R10: 0000000000000000 R11: 0000000000000293 R12: 0000555556ef3810 R13: 0000555556ef386b R14: 0000000000000014 R15: 00007fff2ed1a5f0 INFO: task kworker/u4:5:24083 blocked for more than 140 seconds. Not tainted 4.14.281-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:5 D26696 24083 2 0x80000000 Workqueue: events_unbound fsnotify_connector_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_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/u4:2:25605 blocked for more than 140 seconds. Not tainted 4.14.281-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:2 D25992 25605 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 INFO: task syz-executor.0:25094 blocked for more than 140 seconds. Not tainted 4.14.281-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29120 25094 7993 0x80000002 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 _synchronize_rcu_expedited+0x522/0x770 kernel/rcu/tree_exp.h:615 synchronize_rcu+0x98/0x130 kernel/rcu/tree_plugin.h:762 caif_disconnect_client+0xb8/0x1d0 net/caif/cfcnfg.c:197 caif_release+0x174/0x340 net/caif/caif_socket.c:926 __sock_release+0xcd/0x2b0 net/socket.c:602 sock_close+0x15/0x20 net/socket.c:1139 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa44/0x2850 kernel/exit.c:868 do_group_exit+0x100/0x2e0 kernel/exit.c:965 get_signal+0x38d/0x1ca0 kernel/signal.c:2412 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:792 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath+0x295/0x320 arch/x86/entry/common.c:270 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:397 RIP: 0033:0x7f9449edb531 RSP: 002b:00007f94485dc2f0 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007f94485dc700 RCX: 00007f9449edb531 RDX: 00007f94485dc9d0 RSI: 00007f94485dc2f0 RDI: 00000000003d0f00 RBP: 00007fff2ed1a460 R08: 00007f94485dc700 R09: 00007f94485dc700 R10: 00007f94485dc9d0 R11: 0000000000000206 R12: 00007fff2ed1a2ce R13: 00007fff2ed1a2cf R14: 00007f94485dc300 R15: 0000000000022000 INFO: task syz-executor.3:25129 blocked for more than 140 seconds. Not tainted 4.14.281-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28912 25129 7997 0x00000004 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_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 exp_funnel_lock kernel/rcu/tree_exp.h:305 [inline] _synchronize_rcu_expedited+0x32d/0x770 kernel/rcu/tree_exp.h:596 synchronize_rcu+0x98/0x130 kernel/rcu/tree_plugin.h:762 caif_disconnect_client+0xb8/0x1d0 net/caif/cfcnfg.c:197 caif_release+0x174/0x340 net/caif/caif_socket.c:926 __sock_release+0xcd/0x2b0 net/socket.c:602 sock_close+0x15/0x20 net/socket.c:1139 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 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+0x46/0xbb RIP: 0033:0x7feac8cc6d4b RSP: 002b:00007fff220f4960 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007feac8cc6d4b RDX: 00007feac8e32b80 RSI: ffffffffffffffff RDI: 0000000000000003 RBP: 00007feac8e28960 R08: 0000000000000000 R09: 00007feac8e32b88 R10: 00007fff220f4a60 R11: 0000000000000293 R12: 000000000032edca R13: 00007fff220f4a60 R14: 00007feac8e26f60 R15: 0000000000000032 Showing all locks held in the system: 1 lock held by khungtaskd/1529: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by kworker/u4:5/24083: #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/u4:2/25605: #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 3 locks held by kworker/0:1/32082: #0: ("events_power_efficient"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: ((sync_cmos_work).work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 #2: (&rtc->ops_lock){+.+.}, at: [] rtc_set_time drivers/rtc/interface.c:68 [inline] #2: (&rtc->ops_lock){+.+.}, at: [] rtc_set_time+0x55/0x380 drivers/rtc/interface.c:60 3 locks held by syz-executor.0/25094: #0: (&sb->s_type->i_mutex_key#13){+.+.}, at: [] inode_lock include/linux/fs.h:719 [inline] #0: (&sb->s_type->i_mutex_key#13){+.+.}, at: [] __sock_release+0x86/0x2b0 net/socket.c:601 #1: (sk_lock-AF_CAIF){+.+.}, at: [] lock_sock include/net/sock.h:1473 [inline] #1: (sk_lock-AF_CAIF){+.+.}, at: [] caif_release+0xda/0x340 net/caif/caif_socket.c:922 #2: (rcu_preempt_state.exp_mutex){+.+.}, at: [] exp_funnel_lock kernel/rcu/tree_exp.h:272 [inline] #2: (rcu_preempt_state.exp_mutex){+.+.}, at: [] _synchronize_rcu_expedited+0x2c2/0x770 kernel/rcu/tree_exp.h:596 3 locks held by syz-executor.3/25129: #0: (&sb->s_type->i_mutex_key#13){+.+.}, at: [] inode_lock include/linux/fs.h:719 [inline] #0: (&sb->s_type->i_mutex_key#13){+.+.}, at: [] __sock_release+0x86/0x2b0 net/socket.c:601 #1: (sk_lock-AF_CAIF){+.+.}, at: [] lock_sock include/net/sock.h:1473 [inline] #1: (sk_lock-AF_CAIF){+.+.}, at: [] caif_release+0xda/0x340 net/caif/caif_socket.c:922 #2: (rcu_preempt_state.exp_mutex){+.+.}, at: [] exp_funnel_lock kernel/rcu/tree_exp.h:305 [inline] #2: (rcu_preempt_state.exp_mutex){+.+.}, at: [] _synchronize_rcu_expedited+0x32d/0x770 kernel/rcu/tree_exp.h:596 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1529 Comm: khungtaskd Not tainted 4.14.281-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3079 Comm: kworker/1:1 Not tainted 4.14.281-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events rtc_timer_do_work task: ffff88809ba94380 task.stack: ffff88808d808000 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:23 [inline] RIP: 0010:preempt_latency_stop kernel/sched/core.c:3124 [inline] RIP: 0010:preempt_count_sub+0x53/0x130 kernel/sched/core.c:3144 RSP: 0018:ffff88808d80fab8 EFLAGS: 00000202 RAX: 0000000080000001 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000004 RSI: ffff88809ba94c58 RDI: 0000000000000001 RBP: ffff888237956a00 R08: ffff888237956a20 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff11011b01f5e FS: 0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8210976000 CR3: 00000000a195d000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x66/0xe0 kernel/locking/spinlock.c:192 spin_unlock_irqrestore include/linux/spinlock.h:372 [inline] __wake_up_common_lock+0xcd/0x140 kernel/sched/wait.c:127 rtc_handle_legacy_irq+0x121/0x180 drivers/rtc/interface.c:523 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: 08 84 d2 0f 85 c5 00 00 00 8b 0d 49 f9 b3 0a 85 c9 75 18 65 8b 05 4e 5b c9 7e 25 ff ff ff 7f 39 c3 7f 1a 81 fb fe 00 00 00 76 55 <65> 8b 05 36 5b c9 7e f7 db 65 01 1d 2d 5b c9 7e 5b c3 e8 06 98 ---------------- Code disassembly (best guess): 0: 08 84 d2 0f 85 c5 00 or %al,0xc5850f(%rdx,%rdx,8) 7: 00 00 add %al,(%rax) 9: 8b 0d 49 f9 b3 0a mov 0xab3f949(%rip),%ecx # 0xab3f958 f: 85 c9 test %ecx,%ecx 11: 75 18 jne 0x2b 13: 65 8b 05 4e 5b c9 7e mov %gs:0x7ec95b4e(%rip),%eax # 0x7ec95b68 1a: 25 ff ff ff 7f and $0x7fffffff,%eax 1f: 39 c3 cmp %eax,%ebx 21: 7f 1a jg 0x3d 23: 81 fb fe 00 00 00 cmp $0xfe,%ebx 29: 76 55 jbe 0x80 * 2b: 65 8b 05 36 5b c9 7e mov %gs:0x7ec95b36(%rip),%eax # 0x7ec95b68 <-- trapping instruction 32: f7 db neg %ebx 34: 65 01 1d 2d 5b c9 7e add %ebx,%gs:0x7ec95b2d(%rip) # 0x7ec95b68 3b: 5b pop %rbx 3c: c3 retq 3d: e8 .byte 0xe8 3e: 06 (bad) 3f: 98 cwtl