INFO: task kworker/u4:8:4152 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:8 D27112 4152 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 bond1026: making interface bridge964 the new active one schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2713 flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:554 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Showing all locks held in the system: bond1026: Enslaving bridge964 as an active interface with an up link 3 locks held by kworker/1:1/33: #0: 0000000046fc578e ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000003066f082 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000247df374 (rtnl_mutex){+.+.}, at: addrconf_dad_work+0x9c/0x10a0 net/ipv6/addrconf.c:3989 bond809: making interface bridge745 the new active one 1 lock held by khungtaskd/1571: #0: 00000000304ed64f (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 bond809: Enslaving bridge745 as an active interface with an up link 1 lock held by in:imklog/7805: #0: 00000000d26b0d9a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 4 locks held by kworker/u4:9/10627: #0: 00000000499b5b2a (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 00000000499b5b2a (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 #1: 00000000304ed64f (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:428 [inline] #1: 00000000304ed64f (rcu_read_lock){....}, at: update_curr+0x2c3/0x870 kernel/sched/fair.c:857 #2: 0000000075ff13e2 (&base->lock){-.-.}, at: __mod_timer kernel/time/timer.c:1046 [inline] #2: 0000000075ff13e2 (&base->lock){-.-.}, at: mod_timer+0x343/0x1010 kernel/time/timer.c:1114 bond668: making interface bridge621 the new active one #3: 00000000e5764b45 (&obj_hash[i].lock){-.-.}, at: debug_object_activate+0x12f/0x450 lib/debugobjects.c:472 2 locks held by kworker/1:0/8371: #0: 0000000036ad1d22 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 bond668: Enslaving bridge621 as an active interface with an up link #1: 00000000539dc3dd ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 2 locks held by kworker/u4:2/3702: bond802: making interface bridge735 the new active one 3 locks held by kworker/u4:8/4152: bond802: Enslaving bridge735 as an active interface with an up link #0: 00000000211f2f61 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000e0d08daf (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000648e0da9 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 2 locks held by kworker/0:4/22136: #0: 00000000e298d73e ((wq_completion)"rcu_gp"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000ec3faa1b ((work_completion)(&rew.rew_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 2 locks held by syz-executor.4/7618: #0: 000000006f59abb0 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 000000006f59abb0 (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598 #1: 0000000049e34470 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #1: 0000000049e34470 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667 2 locks held by syz-executor.5/7620: #0: 00000000cc834a2f (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 00000000cc834a2f (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598 #1: 0000000049e34470 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #1: 0000000049e34470 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x256/0x6f0 kernel/rcu/tree_exp.h:667 1 lock held by syz-executor.1/7621: #0: 0000000044219522 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 0000000044219522 (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598 1 lock held by syz-executor.3/7622: #0: 00000000f52d8711 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 00000000f52d8711 (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1571 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023 RIP: 0010:find_held_lock+0x2/0x210 kernel/locking/lockdep.c:3514 Code: fd ff ff e8 00 a3 4d 00 e9 ca fe ff ff 48 c7 c7 88 82 f1 89 e8 7f a3 4d 00 e9 23 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 41 57 <49> 89 f7 41 56 49 89 ce 41 55 44 8d 6a ff 49 63 c5 41 54 48 8d 04 RSP: 0018:ffff8880b5a67b30 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffffffff8d243760 RCX: ffff8880b5a67b78 RDX: 0000000000000001 RSI: ffffffff8d3b90a0 RDI: ffff8880b5a4e280 RBP: ffffffff8d3b90a0 R08: 0000000000000286 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff11016b4cf6b R13: ffffffff837740f4 R14: ffff8880b5a4e280 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555555958708 CR3: 00000000a0e54000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_release kernel/locking/lockdep.c:3677 [inline] lock_release+0x246/0x8b0 kernel/locking/lockdep.c:3927 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_unlock_irqrestore+0x1b/0xe0 kernel/locking/spinlock.c:184 debug_object_free lib/debugobjects.c:651 [inline] debug_object_free+0x1c4/0x380 lib/debugobjects.c:624 destroy_timer_on_stack kernel/time/timer.c:753 [inline] schedule_timeout+0x4e6/0xfe0 kernel/time/timer.c:1822 rcu_gp_kthread+0xdad/0x21c0 kernel/rcu/tree.c:2202 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415