IPVS: set_ctl: invalid protocol: 255 172.20.20.16:20004
BUG: unable to handle kernel NULL pointer dereference at 0000000000000080
IP: [<ffffffff835a0e88>] sock_hold include/net/sock.h:589 [inline]
IP: [<ffffffff835a0e88>] l2tp_session_create+0x948/0x1030 net/l2tp/l2tp_core.c:1809
PGD b12a2067 PUD b415f067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 12614 Comm: syz-executor1 Not tainted 4.4.141-gb1bad9e #69
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d7cc9800 task.stack: ffff8800a43e0000
RIP: 0010:[<ffffffff835a0e88>] [  233.254575] IPVS: set_ctl: invalid protocol: 255 172.20.20.16:20004
 [<ffffffff835a0e88>] sock_hold include/net/sock.h:589 [inline]
 [<ffffffff835a0e88>] l2tp_session_create+0x948/0x1030 net/l2tp/l2tp_core.c:1809
RSP: 0018:ffff8800a43e7b48  EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801d08f2280 RCX: ffffc9000225f000
RDX: 1ffff1003a11e480 RSI: ffffffff8359af63 RDI: ffff8801d08f2400
RBP: ffff8800a43e7bb8 R08: ffff8801d7cca100 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff84638de0 R12: ffff8801d25900a8
R13: ffff8800a43e7cd0 R14: ffff8801d2590000 R15: ffffffff8359aa40
FS:  00007fd5dad5c700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000080 CR3: 00000000b3135000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8113da91 ffff8801d08f22a0 ffff8801d2590158 ffff8801d2590010
 ffffffff838c2480 ffff8801d25900b0 ffff8801d2590150 ffff8801d08f2360
 c2c47a9300000000 ffff8801be8f9100 0000000000000000 ffff8801be8f9130
Call Trace:
 [<ffffffff835a5280>] pppol2tp_connect+0x10f0/0x1910 net/l2tp/l2tp_ppp.c:725
 [<ffffffff82f1eb88>] SYSC_connect+0x1b8/0x300 net/socket.c:1557
 [<ffffffff82f214c4>] SyS_connect+0x24/0x30 net/socket.c:1538
 [<ffffffff838c2b25>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: 00 00 48 8d bb 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 36 06 00 00 48 8b 83 80 01 00 00 <f0> ff 80 80 00 00 00 48 8d 43 20 48 89 c7 48 89 45 b0 e8 91 13 
RIP  [<ffffffff835a0e88>] sock_hold include/net/sock.h:589 [inline]
RIP  [<ffffffff835a0e88>] l2tp_session_create+0x948/0x1030 net/l2tp/l2tp_core.c:1809
 RSP <ffff8800a43e7b48>
CR2: 0000000000000080
---[ end trace 1f5de6c6fe4ba9f7 ]---