==================================================================
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 ffff8801d2008a18 by task syz-executor2/6186

CPU: 0 PID: 6186 Comm: syz-executor2 Not tainted 4.4.153-g5e24b4e #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 f07426aeb77994d3 ffff8800b048f548 ffffffff81e162ed
 ffffea0007480200 ffff8801d2008a18 0000000000000000 ffff8801d2008a18
 0000000000001000 ffff8800b048f580 ffffffff8151b4d9 ffff8801d2008a18
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 ffff8801d2008a00
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8801d2008a00, ffff8801d2008ad0)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
BUG: unable to handle kernel paging request at ffffffff894cffff
IP: [<ffffffff8149027b>] constant_test_bit arch/x86/include/asm/bitops.h:311 [inline]
IP: [<ffffffff8149027b>] PageSlab include/linux/page-flags.h:217 [inline]
IP: [<ffffffff8149027b>] page_mapcount include/linux/mm.h:464 [inline]
IP: [<ffffffff8149027b>] dump_page_badflags+0x1b/0x70 mm/debug.c:85
PGD 440f067 PUD 4410063 PMD 0 
Thread overran stack, or stack corrupted
Oops: 0002 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 6186 Comm: syz-executor2 Not tainted 4.4.153-g5e24b4e #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800a3b84800 task.stack: ffff8800b0488000
RIP: 0010:[<ffffffff8149027b>]  [<ffffffff8149027b>] constant_test_bit arch/x86/include/asm/bitops.h:311 [inline]
RIP: 0010:[<ffffffff8149027b>]  [<ffffffff8149027b>] PageSlab include/linux/page-flags.h:217 [inline]
RIP: 0010:[<ffffffff8149027b>]  [<ffffffff8149027b>] page_mapcount include/linux/mm.h:464 [inline]
RIP: 0010:[<ffffffff8149027b>]  [<ffffffff8149027b>] dump_page_badflags+0x1b/0x70 mm/debug.c:85
RSP: 0018:ffff8800acf94f80  EFLAGS: 00010046
RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc90003645000
RDX: 0000000000000000 RSI: ffffffff83aaae60 RDI: ffffea0007480200
RBP: ffff8800acf94fa8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff858f0274 R12: 0000000000000000
R13: ffffffff83aaae60 R14: ffff8801d2008a00 R15: ffff8801d2008ad0
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:00000000f57d4b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffffffff894cffff CR3: 00000001cf03c000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffea0007480200 0000000000000000 ffffffff83aaae60 ffff8801d2008a00
 ffff8801d2008ad0 ffff8800acf94fe8 ffffffff814902b7 000000c4211fcfe0
 ffffea0007480200 0000000000000000 ffffffff83aaae60 ffff8801d2008a00
Call Trace:
 <UNK> 
Code: e8 1b e5 06 00 eb dd 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb 48 40 f5 31 db <01> 88 ff ff 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 
RIP  [<ffffffff8149027b>] constant_test_bit arch/x86/include/asm/bitops.h:311 [inline]
RIP  [<ffffffff8149027b>] PageSlab include/linux/page-flags.h:217 [inline]
RIP  [<ffffffff8149027b>] page_mapcount include/linux/mm.h:464 [inline]
RIP  [<ffffffff8149027b>] dump_page_badflags+0x1b/0x70 mm/debug.c:85
 RSP <ffff8800acf94f80>
CR2: ffffffff894cffff
---[ end trace 56289efad2dfc1e9 ]---