syzbot

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 6377 Comm: syz-executor7 Not tainted 4.15.0-rc8+ #200
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ip6_xmit+0xc16/0x2090 net/ipv6/ip6_output.c:264
RSP: 0018:ffff8801d215f588 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff8801bcf8e0c0 RCX: ffffffff84b58dbd
RDX: 000000002000ed84 RSI: ffffc90001efc000 RDI: 0000000100076c21
RBP: ffff8801d215f7f8 R08: 1ffff100379f1c01 R09: ffff8801d215f748
R10: ffff8801d215f588 R11: ffffed003a42bef0 R12: 0000000100076951
R13: ffffed003a42bee9 R14: 0000000000000040 R15: ffff8801afc003e4
FS:  00007f4883b19700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000209dd000 CR3: 00000001c63c0003 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139
 l2tp_xmit_core net/l2tp/l2tp_core.c:1096 [inline]
 l2tp_xmit_skb+0x105f/0x1410 net/l2tp/l2tp_core.c:1191
 pppol2tp_sendmsg+0x470/0x670 net/l2tp/l2tp_ppp.c:341
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2020
 __sys_sendmsg+0xe5/0x210 net/socket.c:2054
 SYSC_sendmsg net/socket.c:2065 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2061
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452ee9
RSP: 002b:00007f4883b18c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ee9
RDX: 0000000000000081 RSI: 000000002037ffc8 RDI: 0000000000000014
RBP: 000000000000005a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ef910
R13: 00000000ffffffff R14: 00007f4883b196d4 R15: 0000000000000000
Code: 4d 8b a4 24 18 01 00 00 4d 85 e4 74 67 e8 53 a5 ba fc 49 8d bc 24 d0 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 ce 10 00 00 48 8b 95 e8 fd ff ff 48 b8 00 00 
RIP: ip6_xmit+0xc16/0x2090 net/ipv6/ip6_output.c:264 RSP: ffff8801d215f588
---[ end trace ce7cc404c03a78a0 ]---
Kernel panic - not syncing: Fatal exception in interrupt
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..