INFO: task kworker/u4:5:2203 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:5    D ffff8800a6d57968 24400  2203      2 0x80000000
Workqueue: netns cleanup_net
 ffff8800a6d57968 ffff8800ba2317c0 792f2ca979aa5ccb ffff8800ba2317c0
 0000000000000002 ffff8800ba232000 ffff8801db61f180 ffff8801db61f1a8
 ffff8801db61e898 ffff8800b1e897c0 ffff8800ba2317c0 ffffed0014daa001
Call Trace:
 [<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
 [<ffffffff8270a333>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388
 [<ffffffff8270c492>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8270c492>] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621
 [<ffffffff8221a971>] cleanup_net+0x131/0x860 net/core/net_namespace.c:418
 [<ffffffff81122c25>] process_one_work+0x825/0x1720 kernel/workqueue.c:2064
 [<ffffffff81124004>] worker_thread+0x4e4/0xf50 kernel/workqueue.c:2196
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
3 locks held by kworker/u4:5/2203:
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff81122b0a>] process_one_work+0x70a/0x1720 kernel/workqueue.c:2057
 #1:  (net_cleanup_work){+.+.+.}, at: [<ffffffff81122b42>] process_one_work+0x742/0x1720 kernel/workqueue.c:2061
 #2:  (net_mutex){+.+.+.}, at: [<ffffffff8221a971>] cleanup_net+0x131/0x860 net/core/net_namespace.c:418
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 6195 Comm: syz-executor.1 Not tainted 4.4.174+ #4
task: ffff8801ceddaf80 task.stack: ffff8800b7a98000
RIP: 0010:[<ffffffff8115d344>]  [<ffffffff8115d344>] preempt_count_add+0x14/0x1d0 kernel/sched/core.c:3069
RSP: 0018:ffff8800b7a9f918  EFLAGS: 00000202
RAX: dffffc0000000000 RBX: 0000000000000009 RCX: 1ffffffff0634400
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000001
RBP: ffff8800b7a9f928 R08: ffff8800b7a9fa68 R09: 0000000000000000
R10: 000000000000003c R11: 0000000000000203 R12: 0000000000000001
R13: ffff8800b7a9fa68 R14: ffff8800b7a9fff8 R15: ffff8800b7a98000
FS:  00007f3ac87cc700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001b293f000 CR4: 00000000001606b0
Stack:
 0000000000000009 0000000000000009 ffff8800b7a9f940 ffffffff812aef73
 0000000000000000 ffff8800b7a9f958 ffffffff8112f548 ffff8800b7a9ff80
 ffff8800b7a9f9b0 ffffffff81013549 0000000000000009 000000000000003c
Call Trace:
 [<ffffffff812aef73>] is_module_text_address+0x13/0x50 kernel/module.c:4107
 [<ffffffff8112f548>] __kernel_text_address+0x68/0xa0 kernel/extable.c:103
 [<ffffffff81013549>] print_context_stack+0x59/0xd0 arch/x86/kernel/dumpstack.c:107
 [<ffffffff81012bb9>] dump_trace+0x179/0x390 arch/x86/kernel/dumpstack_64.c:243
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81483f22>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81483f22>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81483f22>] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff81484197>] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601
 [<ffffffff8148475f>] kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:554
 [<ffffffff8147fe9c>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff8147fe9c>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff8147fe9c>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff8147fe9c>] kmem_cache_alloc+0xdc/0x2c0 mm/slub.c:2628
 [<ffffffff814ca46c>] getname_flags+0xcc/0x550 fs/namei.c:135
 [<ffffffff814ce04e>] getname fs/namei.c:206 [inline]
 [<ffffffff814ce04e>] user_path_parent fs/namei.c:2422 [inline]
 [<ffffffff814ce04e>] SYSC_renameat2 fs/namei.c:4472 [inline]
 [<ffffffff814ce04e>] SyS_renameat2+0x16e/0xa60 fs/namei.c:4443
 [<ffffffff814ce9ab>] SYSC_rename fs/namei.c:4594 [inline]
 [<ffffffff814ce9ab>] SyS_rename+0x2b/0x40 fs/namei.c:4592
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
Code: fc ff ff 48 89 7d e8 e8 3b 7c 32 00 48 8b 7d e8 e9 fc fc ff ff 66 90 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 54 41 89 fc 53 <48> c7 c3 80 06 00 84 48 89 da 48 c1 ea 03 0f b6 14 02 48 89 d8 
NMI backtrace for cpu 1
CPU: 1 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #4
task: ffff8801da6c2f80 task.stack: ffff8800001c0000
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800001c7c88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001c7cb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe5f0a71000 CR3: 00000000babe0000 CR4: 00000000001606b0
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001c7cd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001c7d30 ffffffff81ab8252
Call Trace:
 [<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
 [<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1