==================================================================
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 ffff8801d9b10b58 by task syz-executor7/7469

CPU: 0 PID: 7469 Comm: syz-executor7 Not tainted 4.4.153-g5e24b4e #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 e9b0b1dd03778d60 ffff8801cfe47548 ffffffff81e162ed
 ffffea000766c400 ffff8801d9b10b58 0000000000000000 ffff8801d9b10b58
 0000000000001200 ffff8801cfe47580 ffffffff8151b4d9 ffff8801d9b10b58
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
 [<ffffffff82f2b3d4>] __sys_sendmmsg+0x1d4/0x2e0 net/socket.c:2053
 [<ffffffff83014e22>] C_SYSC_sendmmsg net/compat.c:728 [inline]
 [<ffffffff83014e22>] 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
 [<ffffffff838ce1c3>] 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 ffff8801d9b10b40
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8801d9b10b40, ffff8801d9b10c10)
The buggy address belongs to the page:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3879 at kernel/locking/lockdep.c:3190 __lock_acquire+0x265f/0x5270 kernel/locking/lockdep.c:3190()
DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)