l2tp_core: tunl 2: fd 44 wrong protocol, got 1, expected 17
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: 4258 Comm: syzkaller246825 Not tainted 4.16.0-rc2+ #326
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline]
RIP: 0010:sk_dst_get include/net/sock.h:1766 [inline]
RIP: 0010:pppol2tp_session_init net/l2tp/l2tp_ppp.c:596 [inline]
RIP: 0010:pppol2tp_connect+0x10a3/0x1dd0 net/l2tp/l2tp_ppp.c:756
RSP: 0018:ffff8801a92c79a8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8801b0a89140 RCX: ffffffff854ac710
RDX: 0000000000000045 RSI: 0000000049049fbf RDI: 0000000000000228
RBP: ffff8801a92c7c28 R08: 1ffff10035258e77 R09: 0000000000000002
R10: ffff8801a92c7878 R11: 0000000000000000 R12: ffff8801b081f6c0
R13: ffff8801a92c7c00 R14: 0000000000000000 R15: ffff8801a92c7ae0
FS:  00007f46f7992700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020e71000 CR3: 00000001b2387004 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 SYSC_connect+0x213/0x4a0 net/socket.c:1639
 SyS_connect+0x24/0x30 net/socket.c:1620
 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x445ee9
RSP: 002b:00007f46f7991db8 EFLAGS: 00000292 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445ee9
RDX: 0000000000000032 RSI: 0000000020e71000 RDI: 000000000000002e
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 00007ffc7f346ebf R14: 00007f46f79929c0 R15: 000000000000000f
Code: fe ff ff e8 50 44 26 fc 4c 89 fa 49 8d be 28 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 c6 04 02 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 df 09 00 00 4c 89 fa 48 b8 00 00 00 00 00 fc 
RIP: __read_once_size include/linux/compiler.h:188 [inline] RSP: ffff8801a92c79a8
RIP: sk_dst_get include/net/sock.h:1766 [inline] RSP: ffff8801a92c79a8
RIP: pppol2tp_session_init net/l2tp/l2tp_ppp.c:596 [inline] RSP: ffff8801a92c79a8
RIP: pppol2tp_connect+0x10a3/0x1dd0 net/l2tp/l2tp_ppp.c:756 RSP: ffff8801a92c79a8
---[ end trace 05fe723d6efb8eda ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..