INFO: task syz-executor.4:10530 blocked for more than 143 seconds. Not tainted 5.12.0-rc4-next-20210324-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:28728 pid:10530 ppid: 8468 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:4329 [inline] __schedule+0x911/0x2160 kernel/sched/core.c:5079 schedule+0xcf/0x270 kernel/sched/core.c:5158 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+0x137/0x150 kernel/locking/rwsem.c:1407 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1903 raw_release+0x58/0x890 net/can/raw.c:352 __sock_release+0xcd/0x280 net/socket.c:599 sock_close+0x18/0x20 net/socket.c:1258 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:143 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xbfc/0x2a60 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x42c/0x2100 kernel/signal.c:2777 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789 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:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x466459 RSP: 002b:00007f0adab4c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000004 RBX: 000000000056c008 RCX: 0000000000466459 RDX: 0000000000000001 RSI: 0000000000000003 RDI: 000000000000001d RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007fff5b6f0b8f R14: 00007f0adab4c300 R15: 0000000000022000 Showing all locks held in the system: 3 locks held by kworker/u4:4/198: 1 lock held by khungtaskd/1642: #0: ffffffff8bf75360 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6333 1 lock held by khugepaged/1649: 1 lock held by in:imklog/8134: #0: ffff8880290e80f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:961 2 locks held by syz-executor.4/10530: #0: ffff88807e46c210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] #0: ffff88807e46c210 (&sb->s_type->i_mutex_key#13){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:598 #1: ffffffff8d674b90 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1903 1 lock held by syz-executor.4/10833: #0: ffffffff8d674b90 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fa/0x760 net/core/net_namespace.c:470 1 lock held by syz-executor.5/10858: #0: ffffffff8d674b90 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fa/0x760 net/core/net_namespace.c:470 1 lock held by syz-executor.2/10866: #0: ffffffff8d674b90 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2fa/0x760 net/core/net_namespace.c:470 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1642 Comm: khungtaskd Not tainted 5.12.0-rc4-next-20210324-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+0x141/0x1d7 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:253 [inline] watchdog+0xd8e/0xf40 kernel/hung_task.c:338 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 198 Comm: kworker/u4:4 Not tainted 5.12.0-rc4-next-20210324-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:mark_lock+0x27/0x17b0 kernel/locking/lockdep.c:4441 Code: 00 00 90 41 57 41 56 41 55 41 54 41 89 d4 48 ba 00 00 00 00 00 fc ff df 55 53 48 81 ec 18 01 00 00 48 8d 5c 24 38 48 89 3c 24 <48> c7 44 24 38 b3 8a b5 41 48 c1 eb 03 48 c7 44 24 40 18 1a ee 8a RSP: 0018:ffffc9000134f9c0 EFLAGS: 00000086 RAX: 0000000000000004 RBX: ffffc9000134f9f8 RCX: 1ffffffff1f680da RDX: dffffc0000000000 RSI: ffff8880127726a0 RDI: ffff888012771c80 RBP: 0000000000000002 R08: 0000000000000000 R09: ffffffff8fae299f R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002 R13: dffffc0000000000 R14: ffff888012772678 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f7cd8adc58 CR3: 0000000014ed4000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_held_locks+0x9f/0xe0 kernel/locking/lockdep.c:4081 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4099 [inline] lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4167 [inline] lockdep_hardirqs_on_prepare+0x135/0x400 kernel/locking/lockdep.c:4119 trace_hardirqs_on+0x5b/0x1c0 kernel/trace/trace_preemptirq.c:49 __local_bh_enable_ip+0xa0/0x120 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:32 [inline] get_next_corpse net/netfilter/nf_conntrack_core.c:2222 [inline] nf_ct_iterate_cleanup+0x15a/0x450 net/netfilter/nf_conntrack_core.c:2245 nf_conntrack_cleanup_net_list+0x81/0x250 net/netfilter/nf_conntrack_core.c:2432 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:178 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595 process_one_work+0x98d/0x1600 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:294