unregister_netdevice: waiting for lo to become free. Usage count = 1
INFO: task syz-executor3:2582 blocked for more than 120 seconds.
      Not tainted 4.9.58-g3861f0b #75
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 ffff8801cf51c800 ffff8801c5f54a80 ffff8801cf7ca4c0 ffff8801c89fe000
 ffff8801db221518 ffff8801cc89f9f8 ffffffff8389890b 0000000000000246
 ffff8801cf51c800 0000000000000000 ffff8801db221e40 ffff8801db221e68
Call Trace:
 [<ffffffff83899eaf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3626
 [<ffffffff8389a833>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3659
 [<ffffffff8389fe42>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8389fe42>] mutex_lock_nested+0x312/0x870 kernel/locking/mutex.c:621
 [<ffffffff82f14ab5>] copy_net_ns+0x155/0x280 net/core/net_namespace.c:387
 [<ffffffff8119e27f>] create_new_namespaces+0x37f/0x730 kernel/nsproxy.c:106
 [<ffffffff8119e8c1>] copy_namespaces+0x291/0x320 kernel/nsproxy.c:164
 [<ffffffff8112bb99>] copy_process.part.51+0x1c99/0x5d40 kernel/fork.c:1667
 [<ffffffff811300d0>] copy_process kernel/fork.c:1491 [inline]
 [<ffffffff811300d0>] _do_fork+0x1c0/0xd70 kernel/fork.c:1949
 [<ffffffff81130d57>] SYSC_clone kernel/fork.c:2059 [inline]
 [<ffffffff81130d57>] SyS_clone+0x37/0x50 kernel/fork.c:2053
 [<ffffffff81006517>] do_syscall_64+0x197/0x490 arch/x86/entry/common.c:280
 [<ffffffff838aa18d>] entry_SYSCALL64_slow_path+0x25/0x25
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 PID: 514 Comm: khungtaskd Not tainted 4.9.58-g3861f0b #75
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d99ffd00 ffffffff81d91149 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810bd090 ffff8801d99ffd38
 ffffffff81d9c26d 0000000000000001 0000000000000000 ffff8801cf51cc18
Call Trace:
 [<ffffffff81d91149>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d91149>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9c26d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9c3a7>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bd184>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81372220>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81372220>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81372220>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81372220>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119ad0d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838aa36a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
NMI backtrace for cpu 0
CPU: 0 PID: 3112 Comm: rsyslogd Not tainted 4.9.58-g3861f0b #75
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cf719800 task.stack: ffff8801cfc68000
RIP: 0010:[<ffffffff8136a020>] 
c [<ffffffff8136a020>] __sanitizer_cov_trace_pc+0x10/0x60 kernel/kcov.c:49
RSP: 0018:ffff8801cfc6f848  EFLAGS: 00000086
RAX: ffff8801cf719800 RBX: ffff8801c98eb185 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000003 RDI: dffffc0000000000
RBP: ffff8801cfc6f848 R08: ffffed003931d631 R09: ffffed003931d631
R10: 0000000000000001 R11: ffffed003931d630 R12: ffff8801c98eb186
R13: 0000000000000003 R14: ffff8802498eb182 R15: 0000000000000000
FS:  00007fb345bf8700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feab1691140 CR3: 00000001cb6da000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801cfc6f940
c ffffffff81db1269
c ffff8801cfc6f8b8
c ffffffff81e40162
c
 ffff8801024000c0
c 00000000000b258b
c 0000000200c6f8e0
c 0000000200f8df16
c
 1ffff10039f8df17
c 00000002ffffffff
c 000000000000016f
c 0a00000000000003
c
Call Trace:
 [<ffffffff81db1269>] number+0x459/0xa00 lib/vsprintf.c:465
 [<ffffffff81dbc392>] vsnprintf+0xa82/0x16d0 lib/vsprintf.c:2110
 [<ffffffff81dbd320>] sprintf+0xb0/0xe0 lib/vsprintf.c:2246
 [<ffffffff81265b87>] print_time kernel/printk/printk.c:1190 [inline]
 [<ffffffff81265b87>] print_prefix+0x307/0x3a0 kernel/printk/printk.c:1213
 [<ffffffff81265e78>] msg_print_text+0x258/0x2b0 kernel/printk/printk.c:1255
 [<ffffffff8126794a>] syslog_print kernel/printk/printk.c:1305 [inline]
 [<ffffffff8126794a>] do_syslog+0x7fa/0xa80 kernel/printk/printk.c:1459
 [<ffffffff816e88e4>] kmsg_read+0x74/0xa0 fs/proc/kmsg.c:39
 [<ffffffff816bf5cf>] proc_reg_read+0xef/0x170 fs/proc/inode.c:202
 [<ffffffff8156c5f3>] __vfs_read+0x103/0x670 fs/read_write.c:452
 [<ffffffff8156db87>] vfs_read+0x107/0x330 fs/read_write.c:475
 [<ffffffff81571829>] SYSC_read fs/read_write.c:591 [inline]
 [<ffffffff81571829>] SyS_read+0xd9/0x1b0 fs/read_write.c:584
 [<ffffffff838aa0c5>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
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c