l2tp_core: tunl 4: sockfd_lookup(fd=6) returned -9 l2tp_core: tunl 4: sockfd_lookup(fd=6) returned -9 l2tp_core: tunl 4: sockfd_lookup(fd=6) returned -9 l2tp_core: tunl 4: sockfd_lookup(fd=6) returned -9 l2tp_core: tunl 4: sockfd_lookup(fd=6) returned -9 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 1c8d44067 [ 26.347250] PUD 1c83b5067 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 4987 Comm: syz-executor0 Not tainted 4.9.124-g09eb2ba #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801c5409800 task.stack: ffff8801c25f8000 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:ffff8801c25ffab0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801d54c8a00 RCX: 1ffff10038a8141d RDX: 1ffff1003aa990d0 RSI: ffff8801c540a0c8 RDI: ffff8801d54c8680 RBP: ffff8801c25ffb50 R08: ffff8801c540a0e8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d54c8558 R13: 0000000000000000 R14: ffff8801d54c8500 R15: ffff8801c25ffc68 FS: 0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f775fb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000001d02cb000 CR4: 00000000001606f0 Stack: 0000000000000201 ffffffff836c9ec1 ffff8801c25ffad0 ffffffff812383ad ffff8801d54c8500 ffff8801d54c8b58 ffff8801d54c8558 ffff8801d54c8b50 ffff8801d54c8ab0 ffff8801d54c8520 0000000000000000 0000000000000000 Call Trace: [] pppol2tp_connect+0x10d7/0x18f0 net/l2tp/l2tp_ppp.c:718 [] SYSC_connect+0x1b8/0x300 net/socket.c:1575 [] SyS_connect+0x24/0x30 net/socket.c:1556 [] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline] [] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 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 906516487cb5db88 ]---