general protection fault in neigh_flush_dev

Hello,

syzkaller hit the following crash on 6084b576dca2e898f5c101baef151f7bfdbb606d
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.

Unfortunately, I don't have any reproducer for this bug yet.


general protection fault: 0000 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4874 Comm: syz-executor2 Not tainted 4.15.0-rc3-next-20171214+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:neigh_flush_dev+0xba/0x330 net/core/neighbour.c:246
RSP: 0018:ffffc900010ef8c0 EFLAGS: 00010293
RAX: ffff8801e154a0c0 RBX: fb894853e5894855 RCX: ffffffff820e532a
RDX: 0000000000000000 RSI: ffffffff83175ff8 RDI: 0000000000000286
RBP: ffffc900010ef908 R08: 0000000000000001 R09: 0000000000000004
R10: ffffc900010ef888 R11: 0000000000000004 R12: ffffffff822181b0
R13: ffff8801de7ac000 R14: ffff8801de7ac000 R15: ffff8801de7ac000
FS:  00007fe03c405700(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000a6fa38 CR3: 000000020d238000 CR4: 00000000001426e0
Call Trace:
 neigh_ifdown+0x41/0x140 net/core/neighbour.c:293
 addrconf_ifdown+0x57/0x780 net/ipv6/addrconf.c:3590
 addrconf_notify+0x86/0xd50 net/ipv6/addrconf.c:3514
 notifier_call_chain+0x41/0xc0 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x32/0x60 net/core/dev.c:1679
 call_netdevice_notifiers net/core/dev.c:1697 [inline]
 rollback_registered_many+0x330/0x490 net/core/dev.c:7288
 rollback_registered+0x59/0x90 net/core/dev.c:7330
 unregister_netdevice_queue+0xa5/0xf0 net/core/dev.c:8311
 unregister_netdevice include/linux/netdevice.h:2464 [inline]
 __tun_detach+0x618/0x680 drivers/net/tun.c:688
 tun_detach drivers/net/tun.c:699 [inline]
 tun_chr_close+0x26/0x30 drivers/net/tun.c:2955
 __fput+0x120/0x270 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0xa3/0xe0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x3e6/0x1050 kernel/exit.c:869
 do_group_exit+0x60/0x100 kernel/exit.c:972
 get_signal+0x36c/0xad0 kernel/signal.c:2337
 do_signal+0x23/0x670 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x13c/0x160 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x1b4/0x1e0 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x94/0x96
RIP: 0033:0x452a39
RSP: 002b:00007fe03c404ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000007581b8 RCX: 0000000000452a39
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000007581b8
RBP: 00000000007581b8 R08: 0000000000000624 R09: 0000000000758190
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000a6f7ff R14: 00007fe03c4059c0 R15: 000000000000001e
Code: ef 0c 01 00 74 56 e8 36 50 1d ff 49 8b 1c 24 48 85 db 0f 84 98 00 00 00 e8 24 50 1d ff 4d 85 f6 0f 84 c0 00 00 00 e8 16 50 1d ff <4c> 39 b3 80 02 00 00 0f 84 ae 00 00 00 e8 04 50 1d ff e8 ff 4f
RIP: neigh_flush_dev+0xba/0x330 net/core/neighbour.c:246 RSP: ffffc900010ef8c0
---[ end trace b21fc1fec7a05fa5 ]---


---
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