==================================================================
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 ffff8800b60c5a18 by task syz-executor3/31744

CPU: 0 PID: 31744 Comm: syz-executor3 Not tainted 4.4.152-ge5c5f1f #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 78c34ecaf8dc6394 ffff8801cf227548 ffffffff81e15fed
 ffffea0002d83140 ffff8800b60c5a18 0000000000000000 ffff8800b60c5a18
 0000000000001000 ffff8801cf227580 ffffffff8151b489 ffff8800b60c5a18
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
 [<ffffffff82f2b0d4>] __sys_sendmmsg+0x1d4/0x2e0 net/socket.c:2053
 [<ffffffff83014b22>] C_SYSC_sendmmsg net/compat.c:728 [inline]
 [<ffffffff83014b22>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:725
 [<ffffffff81006d94>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d94>] do_fast_syscall_32+0x324/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838cdec3>] sysenter_flags_fixed+0xd/0x1a

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8800b60c5a00
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8800b60c5a00, ffff8800b60c5ad0)
The buggy address belongs to the page:
PANIC: double fault, error_code: 0x0
CPU: 0 PID: 47722816 Comm: syz-exec@1Ø Not tainted 4.4.152-ge5c5f1f #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801caa61800 task.stack:           (null)
RIP: 0010:[<ffffffff8149022a>]  [<ffffffff8149022a>] dump_page_badflags+0x1a/0x70 mm/debug.c:84
RSP: 0018:ffff8800fffffff8  EFLAGS: 00010092
RAX: ffff8801caa61800 RBX: ffffea0002d83140 RCX: ffffc90001032000
RDX: 0000000000000000 RSI: ffffffff83aaae60 RDI: ffffea0002d83140
RBP: ffff880100000028 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff858f0274 R12: 0000000000000000
R13: ffffffff83aaae60 R14: ffff8800b60c5a00 R15: ffff8800b60c5ad0
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:00000000f5750b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000130 CR3: 00000000aee74000 CR4: 00000000001606f0
Stack:
BUG: unable to handle kernel paging request at ffff8800fffffff8
IP: [<ffffffff8111f54d>] show_stack_log_lvl.cold.1+0x73/0x12e arch/x86/kernel/dumpstack_64.c:287
PGD 6330067 PUD 0 
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access[  476.211647] ------------[ cut here ]------------
WARNING: CPU: 0 PID: 47722816 at kernel/sched/core.c:7946 __might_sleep+0x138/0x1a0 kernel/sched/core.c:7941()
do not call blocking ops when !TASK_RUNNING; state=ffffea0002d83140 set at [<ffffffff81490267>] dump_page mm/debug.c:105 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea0002d83140 set at [<ffffffff81490267>] page_mapcount include/linux/mm.h:464 [inline]
do not call blocking ops when !TASK_RUNNING; state=ffffea0002d83140 set at [<ffffffff81490267>] dump_page_badflags+0x57/0x70 mm/debug.c:85