INFO: task syz-executor.4:19303 blocked for more than 143 seconds. Not tainted 5.11.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:28272 pid:19303 ppid: 8484 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 rwsem_down_write_slowpath+0x7e5/0x1200 kernel/locking/rwsem.c:1106 __down_write_common kernel/locking/rwsem.c:1261 [inline] __down_write_common kernel/locking/rwsem.c:1258 [inline] __down_write kernel/locking/rwsem.c:1270 [inline] down_write+0x132/0x150 kernel/locking/rwsem.c:1407 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1868 raw_release+0x58/0x890 net/can/raw.c:352 __sock_release+0xcd/0x280 net/socket.c:597 sock_close+0x18/0x20 net/socket.c:1256 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc5c/0x2ae0 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x427/0x20f0 kernel/signal.c:2773 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811 handle_signal_work kernel/entry/common.c:147 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e219 RSP: 002b:00007fd8790a5c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000004 RBX: 0000000000000003 RCX: 000000000045e219 RDX: 0000000000000001 RSI: 0000000000000003 RDI: 000000000000001d RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffd1ac3e4af R14: 00007fd8790a69c0 R15: 000000000119bf8c Showing all locks held in the system: 3 locks held by kworker/u4:0/8: 1 lock held by khungtaskd/1653: #0: ffffffff8b373da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6259 1 lock held by in:imklog/8159: #0: ffff8880213f99f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947 2 locks held by syz-executor.4/19303: #0: ffff8880180b6c10 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] #0: ffff8880180b6c10 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:596 #1: ffffffff8ca455d0 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1868 1 lock held by syz-executor.4/20157: #0: ffffffff8ca455d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fa/0x760 net/core/net_namespace.c:479 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1653 Comm: khungtaskd Not tainted 5.11.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd43/0xfa0 kernel/hung_task.c:294 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8 Comm: kworker/u4:0 Not tainted 5.11.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:lockdep_hardirqs_off+0x3b/0xd0 kernel/locking/lockdep.c:4190 Code: 7b 1e 08 77 a9 00 00 f0 00 55 53 48 89 fb 74 49 8b 15 09 15 12 06 85 d2 74 0e 65 8b 05 da 2c 08 77 85 c0 75 4e 5b 5d c3 9c 58 c4 02 74 eb e8 8b 09 00 00 85 c0 74 ed 8b 05 d9 e4 09 04 85 c0 RSP: 0018:ffffc90000cd7b48 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffffffff814473d3 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000000 RBP: ffffffff87371b98 R08: 0000000000000000 R09: ffffffff8b0657c3 R10: fffffbfff160caf8 R11: 0000000000000000 R12: ffffffff8b0657c0 R13: 000000000000a835 R14: 0000000000000000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f81b403e3a0 CR3: 0000000026119000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_hardirqs_off+0x13/0x1b0 kernel/trace/trace_preemptirq.c:76 __local_bh_enable_ip+0xc3/0x110 kernel/softirq.c:178 local_bh_enable include/linux/bottom_half.h:32 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2221 [inline] nf_ct_iterate_cleanup+0x11f/0x400 net/netfilter/nf_conntrack_core.c:2244 nf_conntrack_cleanup_net_list+0x81/0x250 net/netfilter/nf_conntrack_core.c:2431 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296