syzbot

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 2299 Comm: kworker/u4:4 Not tainted 4.4.165+ #15
Workqueue: netns cleanup_net
task: ffff8800b4f0df00 task.stack: ffff8801d18a8000
RIP: 0010:[<ffffffff825c55c6>]  [<ffffffff825c55c6>] addrconf_rt_table+0x126/0x290 net/ipv6/addrconf.c:2192
RSP: 0018:ffff8801d18af590  EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000004
RDX: 0000000000000067 RSI: 0000000000000004 RDI: 0000000000000338
RBP: ffff8801d18af5c0 R08: ffff8800b4f0e7c8 R09: 0000000000000001
R10: 0000000000000000 R11: ffffffff831a2db8 R12: 00000000000000fe
R13: ffff8801d2dc3300 R14: 0000000000000218 R15: ffff8800b834a418
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000025d7b30 CR3: 0000000002e0a000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff825c54a0 ffff8801d2dc3300 0000000000000000 ffff8800b2148000
 ffff8801d2f27700 ffff8800b834a418 ffff8801d18af608 ffffffff825c5e33
 00000000b834a280 ffff880100000080 ffff8800b834a280 ffff8800b834a418
Call Trace:
 [<ffffffff825c5e33>] addrconf_get_prefix_route+0x33/0x270 net/ipv6/addrconf.c:2246
 [<ffffffff825c6662>] __ipv6_ifa_notify+0x5f2/0x760 net/ipv6/addrconf.c:5234
 [<ffffffff825c7cce>] addrconf_ifdown+0x5ce/0xbc0 net/ipv6/addrconf.c:3477
 [<ffffffff825ceb19>] addrconf_notify+0x8d9/0x1a60 net/ipv6/addrconf.c:3339
 [<ffffffff811382f9>] notifier_call_chain+0xb9/0x1e0 kernel/notifier.c:93
 [<ffffffff8113848d>] __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 [<ffffffff8113848d>] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 [<ffffffff8221f995>] call_netdevice_notifiers_info+0x55/0x70 net/core/dev.c:1643
 [<ffffffff8222d144>] call_netdevice_notifiers net/core/dev.c:1659 [inline]
 [<ffffffff8222d144>] rollback_registered_many+0x594/0x9a0 net/core/dev.c:6372
 [<ffffffff822360e5>] unregister_netdevice_many+0x45/0x220 net/core/dev.c:7382
 [<ffffffff822365ff>] default_device_exit_batch+0x33f/0x3f0 net/core/dev.c:7840
 [<ffffffff8220fcf5>] ops_exit_list.isra.0+0x105/0x160 net/core/net_namespace.c:137
 [<ffffffff82212af2>] cleanup_net+0x3f2/0x880 net/core/net_namespace.c:452
 [<ffffffff81123204>] process_one_work+0x824/0x1730 kernel/workqueue.c:2064
 [<ffffffff811241e9>] worker_thread+0xd9/0x1060 kernel/workqueue.c:2196
 [<ffffffff81134788>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff82714505>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 5c 82 be 01 00 00 00 48 c7 c7 60 72 ea 82 e8 52 e4 c3 fe 48 8d bb 38 03 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 39 01 00 00 44 8b bb 38 03 
RIP  [<ffffffff825c55c6>] addrconf_rt_table+0x126/0x290 net/ipv6/addrconf.c:2192
 RSP <ffff8801d18af590>
---[ end trace 4755062df8ded16d ]---