==================================================================
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 ffff8801d8f00c98 by task syz-executor3/9293

CPU: 1 PID: 9293 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 bd1ecfaf1d5e123e ffff8800a39df548 ffffffff81e15fed
 ffffea000763c000 ffff8801d8f00c98 0000000000000000 ffff8801d8f00c98
 0000000000001000 ffff8800a39df580 ffffffff8151b489 ffff8801d8f00c98
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 ffff8801d8f00c80
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 24 bytes inside of
 208-byte region [ffff8801d8f00c80, ffff8801d8f00d50)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access[  118.432691] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffff8800a3937ba8
IP: [<ffff8800a3937ba8>] 0xffff8800a3937ba8
PGD 6330067 PUD 21ffff067 PMD 80000000a38001e3 
Oops: 0011 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 9294 Comm: syz-executor0 Not tainted 4.4.152-ge5c5f1f #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801bb581800 task.stack: ffff8800b9600000
RIP: 0010:[<ffff8800a3937ba8>]  [<ffff8800a3937ba8>] 0xffff8800a3937ba8
RSP: 0018:ffff8801db207d10  EFLAGS: 00010206
RAX: ffff8800a3937ba8 RBX: ffff8801db207d60 RCX: 1ffffffff0748afc
RDX: 0000000000000100 RSI: ffffffff81293ac9 RDI: ffffffff81490267
RBP: ffff8801db207de8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 1ffff1003b640fa8
R13: ffff8800a3937b50 R14: 0000000000000101 R15: ffffffff83a457e0
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:00000000f5743b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffff8800a3937ba8 CR3: 00000001cf047000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff81293adc ffffffff81293a2a ffff8801db207de8 ffffffff81e77b44
 ffffffff81490267 ffff8800a3937ba8 0000000041b58ab3 ffffffff841e50d5
 ffffffff81293950 00000017db2196c0 ffff8801d8f00d50 0000000000000000
Call Trace:
 <IRQ> 
 [<ffffffff81294802>] __run_timers kernel/time/timer.c:1261 [inline]
 [<ffffffff81294802>] run_timer_softirq+0x642/0xb90 kernel/time/timer.c:1444
 [<ffffffff838cfa7c>] __do_softirq+0x22c/0xa1a kernel/softirq.c:273
 [<ffffffff811428cd>] invoke_softirq kernel/softirq.c:350 [inline]
 [<ffffffff811428cd>] irq_exit+0x10d/0x140 kernel/softirq.c:391
 [<ffffffff838cf1e1>] exiting_irq arch/x86/include/asm/apic.h:652 [inline]
 [<ffffffff838cf1e1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:926
 [<ffffffff838ce120>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff8126055e>] vprintk_emit+0x51e/0x840 kernel/printk/printk.c:1832
 [<ffffffff812608a8>] vprintk+0x28/0x30 kernel/printk/printk.c:1843
 [<ffffffff812608cd>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1844
 [<ffffffff814185c1>] printk+0xaf/0xd7 kernel/printk/printk.c:1922
 [<ffffffff81126a2e>] kasan_die_handler.cold.3+0x1d/0x22 arch/x86/mm/kasan_init_64.c:59
 [<ffffffff81197239>] notifier_call_chain+0xb9/0x1e0 kernel/notifier.c:93
 [<ffffffff8119884f>] __atomic_notifier_call_chain kernel/notifier.c:183 [inline]
 [<ffffffff8119884f>] atomic_notifier_call_chain+0x7f/0x140 kernel/notifier.c:193
 [<ffffffff811989ef>] notify_die+0xdf/0x160 kernel/notifier.c:549
 [<ffffffff81010ffa>] do_general_protection+0x20a/0x2b0 arch/x86/kernel/traps.c:461
 [<ffffffff838cd8e8>] general_protection+0x28/0x30 arch/x86/entry/entry_64.S:1036
 [<ffffffff82fa585b>] dst_alloc+0xdb/0x1a0 net/core/dst.c:214
 [<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
 [<ffffffff832da7c0>] udp_sendmsg+0x1480/0x1c70 net/ipv4/udp.c:1040
 [<ffffffff8349fbcd>] udpv6_sendmsg+0x12cd/0x24c0 net/ipv6/udp.c:1173
 [<ffffffff8330a633>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<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
Code: ff ff ff 00 c0 63 07 00 ea ff ff 00 00 00 00 00 00 00 00 60 ae aa 83 ff ff ff ff 80 0c f0 d8 01 88 ff ff 50 0d f0 d8 01 88 ff ff <e8> 7b 93 a3 00 88 ff ff 67 02 49 81 ff ff ff ff 40 ad a6 83 ff 
RIP  [<ffff8800a3937ba8>] 0xffff8800a3937ba8
 RSP <ffff8801db207d10>
CR2: ffff8800a3937ba8
---[ end trace 982808c520d0147b ]---