l2tp_core: tunl 2: sockfd_lookup(fd=7) returned -9
l2tp_core: tunl 2: sockfd_lookup(fd=7) returned -9
BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
IP: [<ffffffff835868b2>] sock_hold include/net/sock.h:584 [inline]
IP: [<ffffffff835868b2>] l2tp_session_create+0xc42/0x1770 net/l2tp/l2tp_core.c:1907
PGD 80000001c3573067 [   30.172950] PUD 1c3514067 
Oops: 0002 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 5197 Comm: syzkaller400578 Not tainted 4.9.78-ge9dabe6 #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c3583000 task.stack: ffff8801c30d8000
RIP: 0010:[<ffffffff835868b2>]  [<ffffffff835868b2>] sock_hold include/net/sock.h:584 [inline]
RIP: 0010:[<ffffffff835868b2>]  [<ffffffff835868b2>] l2tp_session_create+0xc42/0x1770 net/l2tp/l2tp_core.c:1907
RSP: 0018:ffff8801c30dfb18  EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801c365d900 RCX: 0000000000000006
RDX: 1ffff100386cbb00 RSI: ffff8801c35838b0 RDI: ffff8801c365d800
RBP: ffff8801c30dfbb8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c365d6d8
R13: 0000000000007fff R14: 0000000000000000 R15: ffff8801c365d680
FS:  00007f09ce561700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000080 CR3: 00000001c3ade000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000201 ffffffff83587c6e ffff8801c30dfb38 ffffffff8123b7fd
 ffff8801c365d680 ffff8801c365d6d8 ffff8801c365da58 ffff8801c365da50
 ffff8801c365d9b0 ffff8801c365d6a0 0000000000000000 ffff8801c365d760
Call Trace:
 [<ffffffff8358bd0e>] pppol2tp_connect+0x10fe/0x18f0 net/l2tp/l2tp_ppp.c:711
 [<ffffffff82ed86e6>] SYSC_connect+0x1b6/0x310 net/socket.c:1562
 [<ffffffff82edaf44>] SyS_connect+0x24/0x30 net/socket.c:1543
 [<ffffffff838b2c6e>] entry_SYSCALL_64_fastpath+0x29/0xe8
Code: 00 00 49 8d bf 80 01 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 d8 08 00 00 49 8b 87 80 01 00 00 <f0> ff 80 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 55 c8 
RIP  [<ffffffff835868b2>] sock_hold include/net/sock.h:584 [inline]
RIP  [<ffffffff835868b2>] l2tp_session_create+0xc42/0x1770 net/l2tp/l2tp_core.c:1907
 RSP <ffff8801c30dfb18>
CR2: 0000000000000080
---[ end trace 3fff4653b98a0d9b ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..