BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [] sock_hold include/net/sock.h:584 [inline] IP: [] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911 PGD 1bb015067 [ 73.781005] PUD 1bac98067 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 6279 Comm: syz-executor1 Not tainted 4.9.117-g8b21e85 #71 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801a50ec800 task.stack: ffff8801b91f8000 RIP: 0010:[] [] sock_hold include/net/sock.h:584 [inline] RIP: 0010:[] [] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911 RSP: 0018:ffff8801b91ffac0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801da102780 RCX: 1ffff10034a1da1d RDX: 1ffff1003b420660 RSI: ffff8801a50ed0c8 RDI: ffff8801da103300 RBP: ffff8801b91ffb60 R08: ffff8801a50ed0e8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801da1031d8 R13: 0000000000000000 R14: ffff8801da103180 R15: 0000000000000000 FS: 00007fee5e1f0700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000001bb256000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff836c4007 ffffffff836c50a1 ffff8801bfb5dd48 0000000000000000 ffff8801da103180 ffff8801da1028d8 ffff8801da1031d8 ffff8801da1028d0 ffff8801da102830 ffff8801da1031a0 ffff8801bfb5d500 0000000000000000 Call Trace: [] pppol2tp_connect+0x10d7/0x18f0 net/l2tp/l2tp_ppp.c:718 [] SYSC_connect+0x1b8/0x300 net/socket.c:1562 [] SyS_connect+0x24/0x30 net/socket.c:1543 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Code: 00 00 49 8d be 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 7b 09 00 00 49 8b 86 80 01 00 00 ff 80 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 55 d0 RIP [] sock_hold include/net/sock.h:584 [inline] RIP [] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911 RSP CR2: 0000000000000080 ---[ end trace 7e2a5cd751c79b80 ]---