IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready l2tp_core: tunl 4: sockfd_lookup(fd=5) returned -9 l2tp_core: tunl 4: sockfd_lookup(fd=5) returned -9 BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 IP: [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1671 PGD b5a94067 PUD b52a1067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 5749 Comm: syz-executor0 Not tainted 4.4.151-ge917467 #84 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8800af22e000 task.stack: ffff8800aed00000 RIP: 0010:[] [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1671 RSP: 0018:ffff8800aed07cd8 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff8801cd493400 RCX: 0000000000000000 RDX: 1ffff100162a1260 RSI: ffffffff835a6a11 RDI: ffff8800b1509300 RBP: ffff8800aed07cf8 R08: ffffffff853352c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800b1509180 R13: ffff8801cd493408 R14: 0000000000000000 R15: ffffffff82f22e60 FS: 0000000001d7f940(0063) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000000b3fe4000 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff8801ca604400 ffff8801cd493400 ffff8801ca6047d0 ffff8801ca6046d8 ffff8800aed07d20 ffffffff835b04b7 ffff8801ca604400 ffffffff835b03e0 ffff8800ae77d560 ffff8800aed07d48 ffffffff82f37eec ffff8801ca604400 Call Trace: [] l2tp_session_dec_refcount_1 net/l2tp/l2tp_core.h:293 [inline] [] pppol2tp_session_destruct+0xd7/0x110 net/l2tp/l2tp_ppp.c:477 [] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447 [] __sk_free+0x4f/0x220 net/core/sock.c:1480 [] sk_free+0x30/0x40 net/core/sock.c:1491 [] sock_put include/net/sock.h:1639 [inline] [] pppol2tp_release+0x26a/0x310 net/l2tp/l2tp_ppp.c:518 [] sock_release+0x96/0x1c0 net/socket.c:587 [] sock_close+0x16/0x20 net/socket.c:1038 [] __fput+0x235/0x6f0 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10f/0x190 kernel/task_work.c:115 [] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:253 [] prepare_exit_to_usermode arch/x86/entry/common.c:284 [inline] [] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:349 [] int_ret_from_sys_call+0x25/0xa3 Code: 49 8d bc 24 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 d0 00 00 00 4d 8b b4 24 80 01 00 00 41 ff 8e 80 00 00 00 74 64 e8 b5 db da fd e8 b0 db da fd 4c RIP [] l2tp_session_free+0x11c/0x200 net/l2tp/l2tp_core.c:1671 RSP CR2: 0000000000000080 ---[ end trace 81376f97a217e2e3 ]---