INFO: task kworker/u4:1:23 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/u4:1 D26024 23 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 XFS (loop2): Mounting V4 Filesystem flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 XFS (loop2): Ending clean mount 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 hub 9-0:1.0: USB hub found kthread+0x33f/0x460 kernel/kthread.c:259 hub 9-0:1.0: 8 ports detected ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 INFO: task syz-executor.1:19481 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. syz-executor.1 D26880 19481 8143 0x00000004 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_work+0x4bb/0x8b0 kernel/workqueue.c:2926 EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue __cancel_work_timer+0x412/0x590 kernel/workqueue.c:3013 p9_conn_destroy net/9p/trans_fd.c:904 [inline] p9_fd_close+0x305/0x520 net/9p/trans_fd.c:934 p9_client_create+0x901/0x12e0 net/9p/client.c:1084 v9fs_session_init+0x1dd/0x1770 fs/9p/v9fs.c:421 v9fs_mount+0x73/0x910 fs/9p/vfs_super.c:135 mount_fs+0xa3/0x310 fs/super.c:1261 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2492 [inline] do_mount+0x115c/0x2f50 fs/namespace.c:2822 ksys_mount+0xcf/0x130 fs/namespace.c:3038 __do_sys_mount fs/namespace.c:3052 [inline] __se_sys_mount fs/namespace.c:3049 [inline] __x64_sys_mount+0xba/0x150 fs/namespace.c:3049 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fe4d87250d9 Code: Bad RIP value. RSP: 002b:00007fe4d6c97168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fe4d8844f80 RCX: 00007fe4d87250d9 RDX: 0000000020000100 RSI: 0000000020000080 RDI: 0000000000000000 RBP: 00007fe4d8780ae9 R08: 0000000020000180 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffde3f4dfbf R14: 00007fe4d6c97300 R15: 0000000000022000 XFS (loop2): Unmounting Filesystem Showing all locks held in the system: 3 locks held by kworker/u4:1/23: #0: 00000000dfa20120 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000c148d1d8 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 000000006ac36f8f (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 1 lock held by khungtaskd/1570: #0: 00000000d2905f8a (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 2 locks held by kworker/u4:4/2888: 1 lock held by in:imklog/7800: #0: 000000002804dbe6 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 1 lock held by syz-executor.2/8170: 2 locks held by kworker/0:3/9342: #0: 00000000d0147ec4 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000005142fa3c ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 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: 27571 Comm: syz-executor.2 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 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+0xbc1/0x3ff0 kernel/locking/lockdep.c:3416 Code: df 49 0f af cc 48 c1 e9 31 4c 8d 04 cd 40 75 d1 8c 4c 89 c2 48 c1 ea 03 80 3c 02 00 0f 85 83 25 00 00 48 8b 1c cd 40 75 d1 8c <48> 85 db 74 55 48 83 eb 08 74 4f 48 bd 00 00 00 00 00 fc ff df eb RSP: 0018:ffff8880ba007ba8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff8c80e108 RCX: 0000000000001c64 RDX: 1ffffffff19a4b0c RSI: 000000000afaceea RDI: 0000000000000000 RBP: 0000000000000040 R08: ffffffff8cd25860 R09: 0000000000000002 R10: ffff8880b3478ed8 R11: ffffffff8c66501b R12: 45fb7ae5f3db03eb R13: ffff8880b3478600 R14: ffff8880b3478ef0 R15: 0000000000000001 FS: 00007f4f12736700(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f59f4088e0 CR3: 000000009e44b000 CR4: 00000000003406f0 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_irq include/linux/spinlock_api_smp.h:128 [inline] _raw_spin_lock_irq+0x5b/0x80 kernel/locking/spinlock.c:160 __run_hrtimer kernel/time/hrtimer.c:1467 [inline] __hrtimer_run_queues+0x45d/0xe60 kernel/time/hrtimer.c:1527 hrtimer_interrupt+0x326/0x9e0 kernel/time/hrtimer.c:1585 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1071 [inline] smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1096 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:generic_exec_single+0x317/0x490 kernel/smp.c:154 Code: 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 5a 01 00 00 48 83 3d 61 04 99 08 00 0f 84 db 00 00 00 e8 3e 07 0a 00 48 89 df 57 9d <0f> 1f 44 00 00 45 31 e4 e9 39 fe ff ff e8 27 07 0a 00 0f 0b e9 3a RSP: 0018:ffff8880afbcfb08 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff8880b3478600 RBX: 0000000000000293 RCX: 1ffff1101668f1da RDX: 0000000000000000 RSI: ffffffff81587e32 RDI: 0000000000000293 RBP: 0000000000000200 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880afbcfb80 R13: ffff8880afbcfc40 R14: ffffffff81767200 R15: ffff8880b347863c smp_call_function_single+0x1cf/0x420 kernel/smp.c:299 task_function_call+0xe0/0x170 kernel/events/core.c:115 perf_install_in_context+0x238/0x3c0 kernel/events/core.c:2623 __do_sys_perf_event_open kernel/events/core.c:10924 [inline] __se_sys_perf_event_open+0xe5d/0x2720 kernel/events/core.c:10549 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f4f141e50d9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4f12736168 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f4f14305050 RCX: 00007f4f141e50d9 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 000000002001d000 RBP: 00007f4f14240ae9 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffed163ebaf R14: 00007f4f12736300 R15: 0000000000022000