==================================================================
BUG: KASAN: slab-out-of-bounds in ip6_dst_idev include/net/ip6_fib.h:141 [inline]
BUG: KASAN: slab-out-of-bounds in ip6_xmit+0x177c/0x1a00 net/ipv6/ip6_output.c:237
Read of size 8 at addr ffff8801d1e53f18 by task syz-executor1/5731

CPU: 0 PID: 5731 Comm: syz-executor1 Not tainted 4.4.152-ge5c5f1f #89
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 e8e4edaf9fa4ba28 ffff8800b99c75c8 ffffffff81e15fed
 ffffea00074794c0 ffff8801d1e53f18 0000000000000000 ffff8801d1e53f18
 0000000000001000 ffff8800b99c7600 ffffffff8151b489 ffff8801d1e53f18
Call Trace:
 [<ffffffff81e15fed>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e15fed>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8151b489>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff8151b7a8>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8151b7a8>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814fe734>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff83435efc>] ip6_dst_idev include/net/ip6_fib.h:141 [inline]
 [<ffffffff83435efc>] ip6_xmit+0x177c/0x1a00 net/ipv6/ip6_output.c:237
 [<ffffffff834f60c5>] inet6_csk_xmit+0x245/0x490 net/ipv6/inet6_connection_sock.c:176
 [<ffffffff835a570c>] l2tp_xmit_core net/l2tp/l2tp_core.c:1084 [inline]
 [<ffffffff835a570c>] l2tp_xmit_skb+0xb9c/0xe80 net/l2tp/l2tp_core.c:1179
 [<ffffffff835b1c60>] pppol2tp_sendmsg+0x4e0/0x7d0 net/l2tp/l2tp_ppp.c:355
 [<ffffffff82f2727c>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff82f2727c>] sock_sendmsg+0xcc/0x110 net/socket.c:648
 [<ffffffff82f28a41>] ___sys_sendmsg+0x441/0x880 net/socket.c:1975
 [<ffffffff82f2b02e>] __sys_sendmmsg+0x12e/0x2e0 net/socket.c:2060
 [<ffffffff82f2b215>] SYSC_sendmmsg net/socket.c:2090 [inline]
 [<ffffffff82f2b215>] SyS_sendmmsg+0x35/0x60 net/socket.c:2085
 [<ffffffff838cc565>] entry_SYSCALL_64_fastpath+0x22/0x9e

Allocated by task 5731:
 [<ffffffff81034676>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814fd7d3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814fdab7>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814fdab7>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
 [<ffffffff814fe082>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff814f9b9e>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff814f9b9e>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff814f9b9e>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff814f9b9e>] kmem_cache_alloc+0xbe/0x2a0 mm/slub.c:2628
 [<ffffffff82fa5835>] dst_alloc+0xb5/0x1a0 net/core/dst.c:210
 [<ffffffff831f29c8>] rt_dst_alloc+0x78/0x430 net/ipv4/route.c:1478
 [<ffffffff831fbe8c>] __mkroute_output net/ipv4/route.c:2132 [inline]
 [<ffffffff831fbe8c>] __ip_route_output_key_hash+0x9ac/0x2380 net/ipv4/route.c:2344
 [<ffffffff831fe339>] __ip_route_output_key include/net/route.h:124 [inline]
 [<ffffffff831fe339>] ip_route_output_flow+0x29/0xa0 net/ipv4/route.c:2431
 [<ffffffff832c7f43>] ip_route_connect include/net/route.h:304 [inline]
 [<ffffffff832c7f43>] __ip4_datagram_connect+0x663/0xfe0 net/ipv4/datagram.c:51
 [<ffffffff834e7cf0>] __ip6_datagram_connect+0x1280/0x1960 net/ipv6/datagram.c:105
 [<ffffffff834e83ff>] ip6_datagram_connect+0x2f/0x50 net/ipv6/datagram.c:223
 [<ffffffff83303057>] inet_dgram_connect+0x117/0x200 net/ipv4/af_inet.c:550
 [<ffffffff82f27bf8>] SYSC_connect+0x1b8/0x300 net/socket.c:1570
 [<ffffffff82f2a544>] SyS_connect+0x24/0x30 net/socket.c:1551
 [<ffffffff838cc565>] entry_SYSCALL_64_fastpath+0x22/0x9e

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801d1e53dc0
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 136 bytes to the right of
 208-byte region [ffff8801d1e53dc0, ffff8801d1e53e90)
The buggy address belongs to the page:
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
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 122131648 Comm: ip Not tainted 4.4.152-ge5c5f1f #89
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b3bab000 task.stack:           (null)
RIP: 0010:[<ffffffff82fad786>]  [<ffffffff82fad786>] neigh_flush_dev+0x166/0x6d0 net/core/neighbour.c:210
RSP: 0018:ffff8801bdaf6fc0  EFLAGS: 00010a06
RAX: 1000000000000065 RBX: 8000000000000080 RCX: ffff8800b6ac7240
RDX: 0000000000000000 RSI: ffffffff82fad778 RDI: 8000000000000328
RBP: ffff8801bdaf7050 R08: ffffffff85358450 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8800b3bab000 R12: ffffffff849928a0
R13: ffff8801bcec4400 R14: ffffea00074794c0 R15: dffffc0000000000
FS:  00007fa68997b700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000130 CR3: 00000001d3bf9000 CR4: 00000000001606f0
Stack:
 0000000000000000 ffffffff82fadd14 ffffed0016d58e48 ffff8800b6ac7248
 ffffffff849928a0 ffff8800b6ac7240 0000004c811caf0d ffffffff84992b48
 0000000000000246 ffffffff84992b30 ffffffff84992b30 ffffffff849928a0
Call Trace:
 <UNK> 
Code: 85 db 0f 84 76 03 00 00 e8 d8 6d 3a fe 48 83 7d d0 00 0f 84 92 00 00 00 e8 c8 6d 3a fe 48 8d bb a8 02 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 0f 85 b6 04 00 00 48 8b 45 d0 48 39 83 a8 02 00 
RIP  [<ffffffff82fad786>] neigh_flush_dev+0x166/0x6d0 net/core/neighbour.c:210
 RSP <ffff8801bdaf6fc0>
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access[   94.210460] ------------[ cut here ]------------
WARNING: CPU: 1 PID: 122131648 at kernel/sched/core.c:7946 __might_sleep+0x138/0x1a0 kernel/sched/core.c:7941()
do not call blocking ops when !TASK_RUNNING; state=ffffea00074794c0 set at [<ffffffff81490267>] dump_page mm/debug.c:105 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea00074794c0 set at [<ffffffff81490267>] page_mapcount include/linux/mm.h:464 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea00074794c0 set at [<ffffffff81490267>] dump_page_badflags+0x57/0x70 mm/debug.c:85