==================================================================
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 ffff8801d2129c98 by task syz-executor6/6999

CPU: 0 PID: 6999 Comm: syz-executor6 Not tainted 4.4.153-g5e24b4e #90
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 686702a7fd196e1e ffff8801be4175c8 ffffffff81e162ed
 ffffea0007484a40 ffff8801d2129c98 0000000000000000 ffff8801d2129c98
 0000000000001000 ffff8801be417600 ffffffff8151b4d9 ffff8801d2129c98
Call Trace:
 [<ffffffff81e162ed>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e162ed>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8151b4d9>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff8151b7f8>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8151b7f8>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814fe784>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff834361fc>] ip6_dst_idev include/net/ip6_fib.h:141 [inline]
 [<ffffffff834361fc>] ip6_xmit+0x177c/0x1a00 net/ipv6/ip6_output.c:237
 [<ffffffff834f63c5>] inet6_csk_xmit+0x245/0x490 net/ipv6/inet6_connection_sock.c:176
 [<ffffffff835a5a0c>] l2tp_xmit_core net/l2tp/l2tp_core.c:1084 [inline]
 [<ffffffff835a5a0c>] l2tp_xmit_skb+0xb9c/0xe80 net/l2tp/l2tp_core.c:1179
 [<ffffffff835b1f60>] pppol2tp_sendmsg+0x4e0/0x7d0 net/l2tp/l2tp_ppp.c:355
 [<ffffffff82f2757c>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff82f2757c>] sock_sendmsg+0xcc/0x110 net/socket.c:648
 [<ffffffff82f28d41>] ___sys_sendmsg+0x441/0x880 net/socket.c:1975
 [<ffffffff82f2b32e>] __sys_sendmmsg+0x12e/0x2e0 net/socket.c:2060
 [<ffffffff82f2b515>] SYSC_sendmmsg net/socket.c:2090 [inline]
 [<ffffffff82f2b515>] SyS_sendmmsg+0x35/0x60 net/socket.c:2085
 [<ffffffff838cc865>] entry_SYSCALL_64_fastpath+0x22/0x9e

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801d2129c80
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8801d2129c80, ffff8801d2129d50)
The buggy address belongs to the page:
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffff8801bb7e7b28
IP: [<ffff8801bb7e7b28>] 0xffff8801bb7e7b28
PGD 6330067 PUD 80000001800001e3 
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access[  108.411036] ------------[ cut here ]------------
WARNING: CPU: 1 PID: 122178112 at kernel/sched/core.c:7946 __might_sleep+0x138/0x1a0 kernel/sched/core.c:7941()
do not call blocking ops when !TASK_RUNNING; state=ffffea0007484a40 set at [<ffffffff814902b7>] dump_page mm/debug.c:105 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea0007484a40 set at [<ffffffff814902b7>] page_mapcount include/linux/mm.h:464 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea0007484a40 set at [<ffffffff814902b7>] dump_page_badflags+0x57/0x70 mm/debug.c:85