INFO: task syz-executor.4:11581 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D ffff8800977ef9d8 28768 11581   2183 0x00000004
 ffff8800977ef9d8 ffff8801bc57df00 67b6d616d3f2aa09 ffff8801bc57df00
 0000000000000000 ffff8801bc57e700 ffff8801db61f180 ffff8801db61f1a8
 ffff8801db61e898 ffff8801b470af80 ffff8801bc57df00 ffffed0012efd001
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
 [<ffffffff8221b16a>] copy_net_ns+0xca/0x250 net/core/net_namespace.c:387
 [<ffffffff81136a90>] create_new_namespaces+0x2f0/0x670 kernel/nsproxy.c:95
 [<ffffffff8113709a>] copy_namespaces+0x28a/0x320 kernel/nsproxy.c:150
 [<ffffffff810cd012>] copy_process+0x2472/0x68a0 kernel/fork.c:1522
 [<ffffffff810d186e>] _do_fork+0x14e/0xdc0 kernel/fork.c:1806
 [<ffffffff810d25b7>] SYSC_clone kernel/fork.c:1917 [inline]
 [<ffffffff810d25b7>] SyS_clone+0x37/0x50 kernel/fork.c:1911
 [<ffffffff82718cb7>] tracesys+0x88/0x8d
1 lock held by syz-executor.4/11581:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff8221b16a>] copy_net_ns+0xca/0x250 net/core/net_namespace.c:387
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #4
task: ffff8801da6f2f80 task.stack: ffff8800001c8000
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:ffff8800001cfc88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001cfcb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000e CR3: 00000000b9729000 CR4: 00000000001606b0
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001cfcd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001cfd30 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 
NMI backtrace for cpu 1
CPU: 1 PID: 3801 Comm: syz-executor.2 Not tainted 4.4.174+ #4
task: ffff8800b7d38000 task.stack: ffff8801bbc18000
RIP: 0010:[<ffffffff8115d37c>]  [<ffffffff8115d37c>] preempt_count_add+0x4c/0x1d0 kernel/sched/core.c:3077
RSP: 0018:ffff8801bbc1f840  EFLAGS: 00000246
RAX: 0000000080000001 RBX: ffffffff84000680 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0208922000000046 RDI: 0000000000000001
RBP: ffff8801bbc1f850 R08: ffff8801bbc1f990 R09: 0000000000000000
R10: ffff8801bbc1fbb8 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8801bbc1f990 R14: ffff8801bbc1fff8 R15: ffff8801bbc18000
FS:  00007f345bff2700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000000e CR3: 00000001b7c23000 CR4: 00000000001606b0
Stack:
 0208922000000046 0208922000000046 ffff8801bbc1f868 ffffffff812aef73
 0000000000000000 ffff8801bbc1f880 ffffffff8112f548 ffff8801bbc1fb18
 ffff8801bbc1f8d8 ffffffff81013549 0208922000000046 ffff8801bbc1fbb8
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
 [<ffffffff81b0bd8c>] kmem_cache_zalloc include/linux/slab.h:610 [inline]
 [<ffffffff81b0bd8c>] fill_pool lib/debugobjects.c:99 [inline]
 [<ffffffff81b0bd8c>] __debug_object_init+0x5bc/0x880 lib/debugobjects.c:315
 [<ffffffff81b0c066>] debug_object_init+0x16/0x20 lib/debugobjects.c:367
 [<ffffffff8123ac33>] rcuhead_fixup_activate kernel/rcu/update.c:381 [inline]
 [<ffffffff8123ac33>] rcuhead_fixup_activate+0x23/0x40 kernel/rcu/update.c:370
 [<ffffffff81b0c32a>] debug_object_fixup lib/debugobjects.c:279 [inline]
 [<ffffffff81b0c32a>] debug_object_activate+0x29a/0x470 lib/debugobjects.c:442
 [<ffffffff812446c5>] debug_rcu_head_queue kernel/rcu/rcu.h:75 [inline]
 [<ffffffff812446c5>] __call_rcu.constprop.0+0x35/0x930 kernel/rcu/tree.c:3059
 [<ffffffff81244fd2>] call_rcu+0x12/0x20 kernel/rcu/tree_plugin.h:662
 [<ffffffff81139dad>] __put_cred+0xcd/0x110 kernel/cred.c:149
 [<ffffffff81139e53>] put_cred include/linux/cred.h:274 [inline]
 [<ffffffff81139e53>] abort_creds+0x63/0x80 kernel/cred.c:509
 [<ffffffff819397f8>] keyctl_set_reqkey_keyring+0x138/0x170 security/keys/keyctl.c:1284
 [<ffffffff8193a5bb>] SYSC_keyctl security/keys/keyctl.c:1626 [inline]
 [<ffffffff8193a5bb>] SyS_keyctl+0xdb/0x260 security/keys/keyctl.c:1559
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
Code: 03 0f b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 63 01 00 00 8b 0d 0f 33 ea 02 85 c9 75 07 65 8b 05 94 93 eb 7e <48> b8 00 00 00 00 00 fc ff df 48 89 da 83 e3 07 48 c1 ea 03 83