syzbot

INFO: task syzkaller339629:3850 blocked for more than 120 seconds.
      Not tainted 4.4.118-g5f7f76a #25
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syzkaller339629 D ffff8800ba647a60 28808  3850   3847 0x20020004
 ffff8800ba647a60 0000000000000006 ffff8800bb043000 ffffffff8113bd3a
 ffffed00388c0180 ffff8801c4600c00 ffff8801db21fdb8 ffff8801db21fde0
 ffff8801db21f4d8 ffffffff84217840 ffff8800bb043000 0000000000000000
Call Trace:
 [<ffffffff8376491a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3353
 [<ffffffff82df4161>] __lock_sock+0xf1/0x180 net/core/sock.c:1999
 [<ffffffff82df42e6>] lock_sock_nested+0xf6/0x120 net/core/sock.c:2453
 [<ffffffff833fe486>] lock_sock include/net/sock.h:1493 [inline]
 [<ffffffff833fe486>] ipv6_getorigdst+0x136/0x610 net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:238
 [<ffffffff82f96b4d>] compat_nf_sockopt net/netfilter/nf_sockopt.c:140 [inline]
 [<ffffffff82f96b4d>] compat_nf_getsockopt+0xfd/0x130 net/netfilter/nf_sockopt.c:162
 [<ffffffff8335983a>] compat_ipv6_getsockopt+0x1fa/0x2f0 net/ipv6/ipv6_sockglue.c:1386
 [<ffffffff83106ce5>] inet_csk_compat_getsockopt+0x95/0x120 net/ipv4/inet_connection_sock.c:901
 [<ffffffff8311955d>] compat_tcp_getsockopt+0x3d/0x70 net/ipv4/tcp.c:2956
 [<ffffffff82df1c32>] compat_sock_common_getsockopt+0xb2/0x140 net/core/sock.c:2629
 [<ffffffff82ed92ef>] C_SYSC_getsockopt net/compat.c:504 [inline]
 [<ffffffff82ed92ef>] compat_SyS_getsockopt+0x14f/0x2a0 net/compat.c:487
 [<ffffffff81006d91>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d91>] do_fast_syscall_32+0x321/0x8a0 arch/x86/entry/common.c:459
 [<ffffffff837743ea>] sysenter_flags_fixed+0xd/0x17
1 lock held by syzkaller339629/3850:
 #0:  (sk_lock-AF_INET6){+.+...}, at: [<ffffffff8335981f>] lock_sock include/net/sock.h:1493 [inline]
 #0:  (sk_lock-AF_INET6){+.+...}, at: [<ffffffff8335981f>] compat_ipv6_getsockopt+0x1df/0x2f0 net/ipv6/ipv6_sockglue.c:1385
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 486 Comm: khungtaskd Not tainted 4.4.118-g5f7f76a #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb2b6000 task.stack: ffff8800bac58000
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3e67>]  [<ffffffff810c3e67>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bac5fcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bac5fce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f420 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020b55000 CR3: 00000000ac646000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f420 ffffffff847ef9c0 fffffbfff08fd9ec dffffc0000000000
 ffff8801db31bca0 ffff8800bac5fd00 ffffffff810b999b ffffffff839f63c0
 0000000000000003 ffff8800bac5fd60 ffffffff81d0ef94 ffffffff8141b013
Call Trace:
 [<ffffffff810b999b>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0ef94>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9a34>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81368c5a>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81368c5a>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368c5a>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368c5a>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff81190788>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83772e85>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 6b 2f 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.118-g5f7f76a #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9b49800 task.stack: ffff8801d9b58000
RIP: 0010:[<ffffffff810d0536>]  [<ffffffff810d0536>] native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:49
RSP: 0018:ffff8801d9b5fd98  EFLAGS: 00000246
RAX: 0000000000000007 RBX: ffffffff847ddac8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801d9b4a0cc
RBP: ffff8801d9b5fd98 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: fffffbfff070889c R14: ffffffff847ebe38 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f772fdb0 CR3: 00000000ac646000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d9b5fdd0 ffffffff81027e85 ffff8801d9b60000 ffffffff847ddac8
 fffffbfff070889c ffffffff847ebe38 0000000000000000 ffff8801d9b5fde0
 ffffffff810293fa ffff8801d9b5fdf8 ffffffff81221468 dffffc0000000000
Call Trace:
 [<ffffffff81027e85>] arch_safe_halt arch/x86/include/asm/paravirt.h:117 [inline]
 [<ffffffff81027e85>] default_idle+0x55/0x3c0 arch/x86/kernel/process.c:290
 [<ffffffff810293fa>] arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:281
 [<ffffffff81221468>] default_idle_call+0x48/0x70 kernel/sched/idle.c:93
 [<ffffffff81221b6d>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
 [<ffffffff81221b6d>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
 [<ffffffff81221b6d>] cpu_startup_entry+0x5fd/0x8f0 kernel/sched/idle.c:301
 [<ffffffff810adc64>] start_secondary+0x304/0x3e0 arch/x86/kernel/smpboot.c:242
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