kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 10125 Comm: syz-executor883 Not tainted 4.14.253-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a5630140 task.stack: ffff8880b3ff8000
RIP: 0010:__read_once_size include/linux/compiler.h:185 [inline]
RIP: 0010:sk_dst_get include/net/sock.h:1772 [inline]
RIP: 0010:pppol2tp_session_init+0x1ca/0x4d0 net/l2tp/l2tp_ppp.c:616
RSP: 0018:ffff8880b3fffc50 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880a55fd680 RCX: 1ffffffff1198bad
RDX: 0000000000000045 RSI: ffffffff87ccef40 RDI: 0000000000000228
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000020012
R10: ffff8880a56309f0 R11: ffff8880a5630140 R12: 000000000000278d
R13: 0000000000000002 R14: ffff88809108ea52 R15: ffff88809108ea70
FS:  0000555556922300(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 00000000a5121000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 pppol2tp_connect+0xd11/0x1370 net/l2tp/l2tp_ppp.c:790
 SYSC_connect net/socket.c:1655 [inline]
 SyS_connect+0x1f4/0x240 net/socket.c:1636
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7eff9fcffa69
RSP: 002b:00007fff60a08b98 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00000000000087f6 RCX: 00007eff9fcffa69
RDX: 000000000000002e RSI: 0000000020000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007fff60a08d38 R09: 00007fff60a08d38
R10: 00007fff60a08d38 R11: 0000000000000246 R12: 00007fff60a08bac
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
Code: fa 80 3d ac 7d 6d 03 00 0f 84 25 02 00 00 e8 4e 96 cf fa 48 8d bd 28 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 db 02 00 00 48 8b ad 28 02 00 00 e8 50 78 c0 
RIP: __read_once_size include/linux/compiler.h:185 [inline] RSP: ffff8880b3fffc50
RIP: sk_dst_get include/net/sock.h:1772 [inline] RSP: ffff8880b3fffc50
RIP: pppol2tp_session_init+0x1ca/0x4d0 net/l2tp/l2tp_ppp.c:616 RSP: ffff8880b3fffc50
---[ end trace a4e823e3030a3f1c ]---
----------------
Code disassembly (best guess):
   0:	fa                   	cli
   1:	80 3d ac 7d 6d 03 00 	cmpb   $0x0,0x36d7dac(%rip)        # 0x36d7db4
   8:	0f 84 25 02 00 00    	je     0x233
   e:	e8 4e 96 cf fa       	callq  0xfacf9661
  13:	48 8d bd 28 02 00 00 	lea    0x228(%rbp),%rdi
  1a:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  21:	fc ff df
  24:	48 89 fa             	mov    %rdi,%rdx
  27:	48 c1 ea 03          	shr    $0x3,%rdx
* 2b:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2f:	0f 85 db 02 00 00    	jne    0x310
  35:	48 8b ad 28 02 00 00 	mov    0x228(%rbp),%rbp
  3c:	e8                   	.byte 0xe8
  3d:	50                   	push   %rax
  3e:	78 c0                	js     0x0