NOHZ: local_softirq_pending 08 syz-executor.1 (6370) used greatest stack depth: 25472 bytes left INFO: task kworker/u4:2:6332 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:2 D27168 6332 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x86c/0xe50 kernel/time/timer.c:1723 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 __wait_rcu_gp+0x22f/0x2e0 kernel/rcu/update.c:413 synchronize_rcu.part.0+0x9b/0xa0 kernel/rcu/tree_plugin.h:764 cleanup_net+0x387/0x820 net/core/net_namespace.c:480 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 INFO: task systemd-udevd:10304 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28592 10304 1 0x80000106 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x86c/0xe50 kernel/time/timer.c:1723 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 __wait_rcu_gp+0x22f/0x2e0 kernel/rcu/update.c:413 synchronize_rcu.part.0+0x9b/0xa0 kernel/rcu/tree_plugin.h:764 namespace_unlock+0xcf/0xf0 fs/namespace.c:1448 put_mnt_ns fs/namespace.c:3322 [inline] put_mnt_ns+0x42/0x60 fs/namespace.c:3318 free_nsproxy+0x40/0x1f0 kernel/nsproxy.c:176 switch_task_namespaces+0x8f/0xb0 kernel/nsproxy.c:229 do_exit+0x9f6/0x2ae0 kernel/exit.c:857 do_group_exit+0x100/0x2e0 kernel/exit.c:955 get_signal+0x385/0x1c90 kernel/signal.c:2423 do_signal+0x7c/0x15d0 arch/x86/kernel/signal.c:814 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: 0033:0x7f5b60660840 RSP: 002b:00007ffc5dfff0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: 0000000000000007 RBX: 0000556ad9f0a750 RCX: 00007f5b60660840 RDX: 0000556ad9adafe3 RSI: 00000000000a0800 RDI: 0000556ad9f04ae0 RBP: 00007ffc5dfff240 R08: 0000556ad9ada670 R09: 0000000000000010 R10: 0000556ad9adad0c R11: 0000000000000246 R12: 00007ffc5dfff190 R13: 0000556ad9f0a540 R14: 0000000000000003 R15: 000000000000000e Showing all locks held in the system: 1 lock held by khungtaskd/1057: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 3 locks held by kworker/u4:2/6332: #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x6d8/0x14c0 kernel/workqueue.c:2087 #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x70e/0x14c0 kernel/workqueue.c:2091 #2: (net_mutex){+.+.}, at: [] cleanup_net+0x123/0x820 net/core/net_namespace.c:450 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1057 Comm: khungtaskd Not tainted 4.14.184-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+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f 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+0x5e2/0xb80 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: 10126 Comm: syz-executor.5 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888090818540 task.stack: ffff88807d450000 RIP: 0010:exact_copy_from_user fs/namespace.c:2738 [inline] RIP: 0010:copy_mount_options+0x183/0x2e0 fs/namespace.c:2771 RSP: 0018:ffff88807d457e88 EFLAGS: 00000297 RAX: ffff888090818540 RBX: 00000000000005e4 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff888090819998 RBP: ffff88808bce2b9c R08: 0000000000000001 R09: 0000000000000000 R10: ffff888090818dc8 R11: ffff888090818540 R12: ffff88808bce2180 R13: 0000000000001000 R14: ffff88808bce2b9c R15: 00007ffffffff000 FS: 00007f2ffc6fe700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000151a74d3 CR3: 00000000a883a000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: SYSC_mount fs/namespace.c:3090 [inline] SyS_mount+0x84/0x120 fs/namespace.c:3072 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45f57a RSP: 002b:00007f2ffc6fda68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000050a6c0 RCX: 000000000045f57a RDX: 00007f2ffc6fdae0 RSI: 0000000000000000 RDI: 00007f2ffc6fdb00 RBP: 000000000078bf00 R08: 00007f2ffc6fdb40 R09: 00007f2ffc6fdae0 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000c3e R14: 00000000004ce90a R15: 00007f2ffc6fe6d4 Code: fc ff df 0f b6 04 08 38 d0 7f 08 84 c0 0f 85 1b 01 00 00 48 83 eb 01 44 88 7d ff 74 36 49 89 ee e8 d3 ec c7 ff 0f 1f 00 0f ae e8 <48> 8b 14 24 31 c0 48 29 da 44 8a 3a 0f 1f 00 85 c0 74 a5 e8 b5