BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 212s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=6/256 refcnt=7 in-flight: 18:rtc_timer_do_work pending: defense_work_handler, defense_work_handler, cache_reap, wait_rcu_exp_gp, macvlan_process_broadcast workqueue events_long: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=4/256 refcnt=5 pending: br_fdb_cleanup, br_fdb_cleanup, br_fdb_cleanup, br_fdb_cleanup 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 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=25 pending: batadv_iv_send_outstanding_bat_ogm_packet delayed: batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, batadv_iv_send_outstanding_bat_ogm_packet, batadv_iv_send_outstanding_bat_ogm_packet, batadv_iv_send_outstanding_bat_ogm_packet, batadv_iv_send_outstanding_bat_ogm_packet, batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, batadv_iv_send_outstanding_bat_ogm_packet, batadv_iv_send_outstanding_bat_ogm_packet, batadv_purge_orig, batadv_purge_orig, batadv_purge_orig, batadv_iv_send_outstanding_bat_ogm_packet, batadv_iv_send_outstanding_bat_ogm_packet, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker, batadv_nc_worker pool 2: cpus=1 node=0 flags=0x0 nice=0 hung=212s workers=3 idle: 21789 8795 INFO: task syz-executor.4:4119 blocked for more than 140 seconds. Not tainted 4.14.272-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28912 4119 7992 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 _synchronize_rcu_expedited+0x522/0x770 kernel/rcu/tree_exp.h:615 synchronize_rcu+0x98/0x130 kernel/rcu/tree_plugin.h:762 synchronize_net+0x3a/0x40 net/core/dev.c:8250 packet_release+0x740/0xa80 net/packet/af_packet.c:3109 __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: 0033:0x7f0f0cf1ac8b RSP: 002b:00007ffc19c02420 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f0f0cf1ac8b RDX: 00007f0f0d0a5be0 RSI: ffffffffffffffff RDI: 0000000000000003 RBP: 00007f0f0d07c960 R08: 0000000000000000 R09: 00007f0f0d0a5be8 R10: 00007ffc19c02520 R11: 0000000000000293 R12: 00000000000c152f R13: 00007ffc19c02520 R14: 00007f0f0d07af60 R15: 0000000000000032 Showing all locks held in the system: 1 lock held by khungtaskd/1532: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by syz-executor.4/4119: #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: (rcu_preempt_state.exp_mutex){+.+.}, at: [] exp_funnel_lock kernel/rcu/tree_exp.h:272 [inline] #1: (rcu_preempt_state.exp_mutex){+.+.}, at: [] _synchronize_rcu_expedited+0x2c2/0x770 kernel/rcu/tree_exp.h:596 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1532 Comm: khungtaskd Not tainted 4.14.272-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: 18 Comm: kworker/1:0 Not tainted 4.14.272-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events rtc_timer_do_work task: ffff8880b54b64c0 task.stack: ffff8880b54c0000 RIP: 0010:mark_lock+0xa6/0x1050 kernel/locking/lockdep.c:3168 RSP: 0018:ffff8880b54c7ae8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff8ba2a710 RCX: 1ffff11016a96db7 RDX: 1ffffffff17454e8 RSI: ffff8880b54b6d98 RDI: ffffffff8ba2a740 RBP: ffff8880b54b6d98 R08: ffffffff8b9dd150 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000040 R13: ffff8880b54b64c0 R14: ffff8880b54b6db8 R15: 0000000000000006 FS: 0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdb161f8ff8 CR3: 0000000008e6a000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_held_locks+0xa6/0xf0 kernel/locking/lockdep.c:2854 __trace_hardirqs_on_caller kernel/locking/lockdep.c:2883 [inline] trace_hardirqs_on_caller+0x3a8/0x580 kernel/locking/lockdep.c:2930 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x79/0xe0 kernel/locking/spinlock.c:192 spin_unlock_irqrestore include/linux/spinlock.h:372 [inline] rtc_handle_legacy_irq+0x7a/0x180 drivers/rtc/interface.c:515 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: 50 01 00 00 48 81 eb 50 01 00 00 48 81 c3 00 bb 9e 8b 48 8d 7b 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 07 0c 00 00 4c 89 e0 48 23 43 30 0f 84 9c 00 00 00 b8 01 ---------------- Code disassembly (best guess): 0: 50 push %rax 1: 01 00 add %eax,(%rax) 3: 00 48 81 add %cl,-0x7f(%rax) 6: eb 50 jmp 0x58 8: 01 00 add %eax,(%rax) a: 00 48 81 add %cl,-0x7f(%rax) d: c3 retq e: 00 bb 9e 8b 48 8d add %bh,-0x72b77462(%rbx) 14: 7b 30 jnp 0x46 16: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1d: fc ff df 20: 48 89 fa mov %rdi,%rdx 23: 48 c1 ea 03 shr $0x3,%rdx 27: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) * 2b: 0f 85 07 0c 00 00 jne 0xc38 <-- trapping instruction 31: 4c 89 e0 mov %r12,%rax 34: 48 23 43 30 and 0x30(%rbx),%rax 38: 0f 84 9c 00 00 00 je 0xda 3e: b8 .byte 0xb8 3f: 01 .byte 0x1