INFO: task kworker/u4:7:9441 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/u4:7 D26048 9441 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 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: 3 locks held by kworker/1:1/25: #0: 00000000b7f49b24 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000e9891ae2 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 0000000099e7b055 (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline] #2: 0000000099e7b055 (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314 1 lock held by khungtaskd/1571: #0: 00000000ad2314af (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by in:imklog/7813: #0: 00000000335e7354 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 4 locks held by rs:main Q:Reg/7814: #0: 000000001c3d75a3 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 000000001c3d75a3 (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 #1: 00000000ad2314af (rcu_read_lock){....}, at: do_perf_sw_event kernel/events/core.c:8113 [inline] #1: 00000000ad2314af (rcu_read_lock){....}, at: ___perf_sw_event+0x121/0x570 kernel/events/core.c:8155 #2: 000000008e1a69d1 (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:768 [inline] #2: 000000008e1a69d1 (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x21f/0xf20 fs/ext4/file.c:238 #3: 000000009b05929f (&(&ei->i_raw_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:329 [inline] #3: 000000009b05929f (&(&ei->i_raw_lock)->rlock){+.+.}, at: ext4_do_update_inode fs/ext4/inode.c:5275 [inline] #3: 000000009b05929f (&(&ei->i_raw_lock)->rlock){+.+.}, at: ext4_mark_iloc_dirty+0x23a/0x2b30 fs/ext4/inode.c:5919 3 locks held by kworker/u4:7/9441: #0: 00000000e2df0ca1 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000005f8bd4ea (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 000000004255606c (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 3 locks held by kworker/u4:14/15819: 3 locks held by kworker/0:1/19119: #0: 00000000b7f49b24 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 0000000091d56d8e ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 000000009dc15e72 (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline] #2: 000000009dc15e72 (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314 3 locks held by kworker/0:4/6169: #0: 00000000b7f49b24 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000005b711092 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000b3cf6671 (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline] #2: 00000000b3cf6671 (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314 3 locks held by kworker/0:6/10733: #0: 00000000b7f49b24 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000b60313dc ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000e1945d9d (&smc->clcsock_release_lock){+.+.}, at: smc_clcsock_accept net/smc/af_smc.c:843 [inline] #2: 00000000e1945d9d (&smc->clcsock_release_lock){+.+.}, at: smc_tcp_listen_work+0x191/0xce0 net/smc/af_smc.c:1314 2 locks held by kworker/1:0/1562: #0: 0000000035f29446 ((wq_completion)"rcu_gp"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000004e0262f6 ((work_completion)(&rew.rew_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 2 locks held by syz-executor.1/5022: #0: 000000008fa8546e (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] #0: 000000008fa8546e (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:598 #1: 00000000c71d64a3 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline] #1: 00000000c71d64a3 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1571 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10 Comm: rcu_preempt Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 RIP: 0010:__read_once_size include/linux/compiler.h:263 [inline] RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:2317 [inline] RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:2337 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:2391 [inline] RIP: 0010:__lock_acquire+0xbfd/0x3ff0 kernel/locking/lockdep.c:3416 Code: fc ff df eb 06 48 83 eb 08 74 3d 48 8d 7b 18 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 8c 1e 00 00 4c 3b 63 18 0f 84 f1 fc ff ff <48> 8d 7b 08 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 93 1e 00 00 48 RSP: 0018:ffff8880b5a67820 EFLAGS: 00000096 RAX: 1ffffffff18fd1a7 RBX: ffffffff8c7e8d20 RCX: 000000000000472e RDX: 1ffffffff19a75d6 RSI: 00000000877bb9f2 RDI: ffffffff8c7e8d38 RBP: dffffc0000000000 R08: ffffffff8cd3aeb0 R09: 0000000000000001 R10: ffff8880b5a4eb30 R11: 0000000000000000 R12: f3e1ddd958bce766 R13: ffff8880b5a4e280 R14: ffff8880b5a4eb48 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4d9349c000 CR3: 00000000a17a8000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152 debug_object_deactivate lib/debugobjects.c:540 [inline] debug_object_deactivate+0xfc/0x2e0 lib/debugobjects.c:529 debug_timer_deactivate kernel/time/timer.c:723 [inline] debug_deactivate kernel/time/timer.c:779 [inline] detach_timer kernel/time/timer.c:824 [inline] detach_if_pending+0x82/0x460 kernel/time/timer.c:843 try_to_del_timer_sync+0xaa/0x110 kernel/time/timer.c:1240 del_timer_sync+0x1a4/0x270 kernel/time/timer.c:1305 schedule_timeout+0x4d7/0xfe0 kernel/time/timer.c:1819 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