l2tp_core: tunl 3: sockfd_lookup(fd=26) returned -9 BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [<ffffffff836c3c20>] sock_hold include/net/sock.h:584 [inline] IP: [<ffffffff836c3c20>] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911 PGD 1bd5fe067 [ 296.517522] PUD 1cc84a067 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 27658 Comm: syz-executor4 Not tainted 4.9.118-g856452b #73 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801b6780000 task.stack: ffff8801a3d10000 RIP: 0010:[<ffffffff836c3c20>] [<ffffffff836c3c20>] sock_hold include/net/sock.h:584 [inline] RIP: 0010:[<ffffffff836c3c20>] [<ffffffff836c3c20>] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911 RSP: 0018:ffff8801a3d17ac0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801cb614a00 RCX: 1ffff10036cf011d RDX: 1ffff100396c2920 RSI: ffff8801b67808c8 RDI: ffff8801cb614900 RBP: ffff8801a3d17b60 R08: ffff8801b67808e8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cb6147d8 R13: 0000000000000000 R14: ffff8801cb614780 R15: 0000000000000000 FS: 00007f9fb9c92700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000001ce135000 CR4: 00000000001606f0 Stack: ffffffff836c3e97 ffffffff836c4f31 ffff8801a43a5d48 0000000000000000 ffff8801cb614780 ffff8801cb614b58 ffff8801cb6147d8 ffff8801cb614b50 ffff8801cb614ab0 ffff8801cb6147a0 ffff8801a43a5500 0000000000000000 Call Trace: [<ffffffff836c8dd7>] pppol2tp_connect+0x10d7/0x18f0 net/l2tp/l2tp_ppp.c:718 [<ffffffff83019958>] SYSC_connect+0x1b8/0x300 net/socket.c:1563 [<ffffffff8301c224>] SyS_connect+0x24/0x30 net/socket.c:1544 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [<ffffffff839fca93>] 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 <f0> ff 80 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 55 d0 RIP [<ffffffff836c3c20>] sock_hold include/net/sock.h:584 [inline] RIP [<ffffffff836c3c20>] l2tp_session_create+0xc60/0x16f0 net/l2tp/l2tp_core.c:1911 RSP <ffff8801a3d17ac0> CR2: 0000000000000080 ---[ end trace 946fc7f941009f3c ]---