[<ffffffff824a406f>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
BUG: spinlock lockup suspected on CPU#1, kworker/u4:0/6
 lock: nf_conntrack_locks+0x0/0xe000, .magic: dead4ead, .owner: kworker/u4:0/6, .owner_cpu: 1
CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 4.5.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
 ffffffff82e0a780 ffff8802169a7c10 ffffffff8180b169 ffff8802169a2180
 ffff8802169a7c30 ffffffff811bfed3 ffffffff82e0a780 0000000089173700
 ffff8802169a7c60 ffffffff811bfffb ffffffff82e0a780 ffff8802157d5570
Call Trace:
 [<ffffffff8180b169>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff8180b169>] dump_stack+0x4b/0x72 lib/dump_stack.c:50
 [<ffffffff811bfed3>] spin_dump+0x73/0xc0 kernel/locking/spinlock_debug.c:67
 [<ffffffff811bfffb>] __spin_lock_debug kernel/locking/spinlock_debug.c:117 [inline]
 [<ffffffff811bfffb>] do_raw_spin_lock+0x9b/0x160 kernel/locking/spinlock_debug.c:137
 [<ffffffff824a302b>] __raw_spin_lock include/linux/spinlock_api_smp.h:145 [inline]
 [<ffffffff824a302b>] _raw_spin_lock+0x3b/0x50 kernel/locking/spinlock.c:151
 [<ffffffff820427ed>] spin_lock include/linux/spinlock.h:302 [inline]
 [<ffffffff820427ed>] nf_conntrack_lock+0xd/0x50 net/netfilter/nf_conntrack_core.c:74
 [<ffffffff8205b96c>] ctnl_untimeout.isra.4+0xdc/0x110 net/netfilter/nfnetlink_cttimeout.c:315
 [<ffffffff8205b9c8>] cttimeout_net_exit+0x28/0x80 net/netfilter/nfnetlink_cttimeout.c:581
 [<ffffffff81fb0a63>] ops_exit_list.isra.4+0x33/0x60 net/core/net_namespace.c:134
 [<ffffffff81fb1ce9>] cleanup_net+0x1a9/0x270 net/core/net_namespace.c:431
 [<ffffffff81187585>] process_one_work+0x215/0x650 kernel/workqueue.c:2036
 [<ffffffff81187a09>] worker_thread+0x49/0x490 kernel/workqueue.c:2170
 [<ffffffff8118e6e9>] kthread+0xf9/0x110 kernel/kthread.c:209
 [<ffffffff824a406f>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.5.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffffffff82e21540 ti: ffffffff82e00000 task.ti: ffffffff82e00000
RIP: 0010:[<ffffffff810c3676>]  [<ffffffff810c3676>] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:50
RSP: 0018:ffffffff82e03eb8  EFLAGS: 00000282
RAX: 0000000000000000 RBX: ffffffff82e00000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff810876d9
RBP: ffffffff82e03eb8 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff82e00000
FS:  0000000000000000(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000481420 CR3: 00000000b9c88000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff82e03ed8 ffffffff810876e8 ffffffff82e00000 ffffffff82e04000
 ffffffff82e03ee8 ffffffff8108803a ffffffff82e03ef8 ffffffff811b3bd5
 ffffffff82e03f40 ffffffff811b3fb7 ffffffff82e04000 9b64ffb15f2c34b6
Call Trace:
 [<ffffffff810876e8>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff810876e8>] default_idle+0x28/0x160 arch/x86/kernel/process.c:304
 [<ffffffff8108803a>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:295
 [<ffffffff811b3bd5>] default_idle_call+0x25/0x50 kernel/sched/idle.c:92
 [<ffffffff811b3fb7>] cpuidle_idle_call kernel/sched/idle.c:150 [inline]
 [<ffffffff811b3fb7>] cpu_idle_loop kernel/sched/idle.c:246 [inline]
 [<ffffffff811b3fb7>] cpu_startup_entry+0x3b7/0x440 kernel/sched/idle.c:294
 [<ffffffff8249a405>] rest_init+0x135/0x140 init/main.c:412
 [<ffffffff8304eff0>] start_kernel+0x4a6/0x4b3 init/main.c:683
 [<ffffffff8304e345>] x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:203
 [<ffffffff8304e48c>] x86_64_start_kernel+0x145/0x152 arch/x86/kernel/head64.c:184
Code: 00 00 00 00 00 55 48 89 e5 fa 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 66 0f 1f 84 
NMI backtrace for cpu 1
CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 4.5.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
task: ffff8802169a2180 ti: ffff8802169a4000 task.ti: ffff8802169a4000
RIP: 0010:[<ffffffff810c3a66>]  [<ffffffff810c3a66>] native_write_msr_safe+0x6/0x40 arch/x86/include/asm/msr.h:132
RSP: 0018:ffff8802169a7b68  EFLAGS: 00000086
RAX: 0000000000000400 RBX: ffffffff8301c5a0 RCX: 0000000000000830
RDX: 0000000000000001 RSI: 0000000000000400 RDI: 0000000000000830
RBP: ffff8802169a7b70 R08: 0000000000000400 R09: 0000000000000003
R10: ffff8802169a2a18 R11: 0000000000000001 R12: 0000000000080000
R13: 0000000000000001 R14: 0000000000000001 R15: 000000000000a130
FS:  0000000000000000(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056007cb90000 CR3: 0000000002e1a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff810bd7fa ffff8802169a7bb8 ffffffff810bd8af 0000000000000282
 0000000200000010 0000000000011440 0000000000000001 ffffffff810ba4c0
 0000000089173700 0000000000000001 ffff8802169a7bc8 ffffffff810bd97e
Call Trace:
 [<ffffffff810bd8af>] __x2apic_send_IPI_mask+0xaf/0x120 arch/x86/kernel/apic/x2apic_phys.c:62
 [<ffffffff810bd97e>] x2apic_send_IPI_mask+0xe/0x10 arch/x86/kernel/apic/x2apic_cluster.c:87
 [<ffffffff810ba4d6>] nmi_raise_cpu_backtrace+0x16/0x20 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff8180fa33>] nmi_trigger_all_cpu_backtrace+0x243/0x250 lib/nmi_backtrace.c:85
 [<ffffffff810ba534>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff811c0005>] trigger_all_cpu_backtrace include/linux/nmi.h:41 [inline]
 [<ffffffff811c0005>] __spin_lock_debug kernel/locking/spinlock_debug.c:119 [inline]
 [<ffffffff811c0005>] do_raw_spin_lock+0xa5/0x160 kernel/locking/spinlock_debug.c:137
 [<ffffffff824a302b>] __raw_spin_lock include/linux/spinlock_api_smp.h:145 [inline]
 [<ffffffff824a302b>] _raw_spin_lock+0x3b/0x50 kernel/locking/spinlock.c:151
 [<ffffffff820427ed>] spin_lock include/linux/spinlock.h:302 [inline]
 [<ffffffff820427ed>] nf_conntrack_lock+0xd/0x50 net/netfilter/nf_conntrack_core.c:74
 [<ffffffff8205b96c>] ctnl_untimeout.isra.4+0xdc/0x110 net/netfilter/nfnetlink_cttimeout.c:315
 [<ffffffff8205b9c8>] cttimeout_net_exit+0x28/0x80 net/netfilter/nfnetlink_cttimeout.c:581
 [<ffffffff81fb0a63>] ops_exit_list.isra.4+0x33/0x60 net/core/net_namespace.c:134
 [<ffffffff81fb1ce9>] cleanup_net+0x1a9/0x270 net/core/net_namespace.c:431
 [<ffffffff81187585>] process_one_work+0x215/0x650 kernel/workqueue.c:2036
 [<ffffffff81187a09>] worker_thread+0x49/0x490 kernel/workqueue.c:2170
 [<ffffffff8118e6e9>] kthread+0xf9/0x110 kernel/kthread.c:209
 [<ffffffff824a406f>] ret_from_fork+0x3f/0x70 arch/x86/entry/entry_64.S:468
Code: 5b 5d c3 48 c1 e2 20 48 89 d3 31 d2 48 09 c3 48 89 de e8 9e 07 78 00 48 89 d8 5b 5d c3 0f 1f 84 00 00 00 00 00 89 f0 89 f9 0f 30 <31> c0 0f 1f 44 00 00 c3 55 41 89 f0 48 89 d6 48 c1 e6 20 89 c2