syzbot

IPVS: ftp: loaded support on port[0] = 21
nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based  firewall rule not found. Use the iptables CT target to attach helpers instead.
skbuff: skb_under_panic: text:00000000e93ca143 len:48 put:8 head:00000000946fb9c9 data:0000000094f10a8e tail:0x2c end:0xc0 dev:sit1
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:104!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8171 Comm: syz-executor886 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:skb_panic+0x172/0x174 net/core/skbuff.c:104
Code: 4c 24 10 8b 8b 80 00 00 00 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 60 4f 4c 89 ff 74 24 10 ff 74 24 20 e8 f1 18 e2 ff <0f> 0b e8 7f e7 50 f9 4c 8b 64 24 18 e8 c5 aa 86 f9 48 c7 c1 c0 58
RSP: 0018:ffff888091c4eb30 EFLAGS: 00010282
RAX: 0000000000000083 RBX: ffff8880a2c5c200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff814dff01 RDI: ffffed1012389d58
RBP: ffffffff894c58c0 R08: 0000000000000083 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffffffff86eec28f
R13: 0000000000000008 R14: ffff8880b0566700 R15: 00000000000000c0
FS:  00005555558d8300(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009bb95000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_under_panic net/core/skbuff.c:114 [inline]
 skb_push.cold+0x24/0x24 net/core/skbuff.c:1730
 fou_build_udp+0x2f/0x360 net/ipv4/fou.c:960
 gue_build_header+0xf7/0x140 net/ipv4/fou.c:1003
 ip_tunnel_encap include/net/ip_tunnels.h:384 [inline]
 ip_tunnel_xmit+0x7ed/0x3850 net/ipv4/ip_tunnel.c:722
 sit_tunnel_xmit__ net/ipv6/sit.c:1017 [inline]
 sit_tunnel_xmit+0x4ef/0x28d0 net/ipv6/sit.c:1033
 __netdev_start_xmit include/linux/netdevice.h:4349 [inline]
 netdev_start_xmit include/linux/netdevice.h:4363 [inline]
 xmit_one net/core/dev.c:3256 [inline]
 dev_hard_start_xmit+0x1a8/0x920 net/core/dev.c:3272
 __dev_queue_xmit+0x269d/0x2e00 net/core/dev.c:3838
 neigh_output include/net/neighbour.h:501 [inline]
 ip_finish_output2+0xd76/0x15a0 net/ipv4/ip_output.c:230
 ip_finish_output+0xae9/0x10b0 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_mc_output+0x268/0xec0 net/ipv4/ip_output.c:391
 dst_output include/net/dst.h:455 [inline]
 ip_local_out+0xaf/0x170 net/ipv4/ip_output.c:125
 ip_send_skb+0x3e/0xe0 net/ipv4/ip_output.c:1452
 udp_send_skb+0x6a4/0x1170 net/ipv4/udp.c:848
 udp_sendmsg+0x1cb4/0x2550 net/ipv4/udp.c:1135
 udpv6_sendmsg+0x14b2/0x2ae0 net/ipv6/udp.c:1224
 inet_sendmsg+0x132/0x5a0 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:661
 ___sys_sendmsg+0x3b3/0x8e0 net/socket.c:2227
 __sys_sendmmsg+0x195/0x470 net/socket.c:2322
 __do_sys_sendmmsg net/socket.c:2351 [inline]
 __se_sys_sendmmsg net/socket.c:2348 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2348
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f60d3630499
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcd81b9eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f60d3630499
RDX: 0000000000000001 RSI: 00000000200017c0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000d369de40 R09: 00000000d369de40
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000008b1f
R13: 00007ffcd81b9ee0 R14: 00007ffcd81b9ed0 R15: 00007ffcd81b9ec4
Modules linked in:
---[ end trace 70e215b8f1dc5818 ]---
RIP: 0010:skb_panic+0x172/0x174 net/core/skbuff.c:104
Code: 4c 24 10 8b 8b 80 00 00 00 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 60 4f 4c 89 ff 74 24 10 ff 74 24 20 e8 f1 18 e2 ff <0f> 0b e8 7f e7 50 f9 4c 8b 64 24 18 e8 c5 aa 86 f9 48 c7 c1 c0 58
RSP: 0018:ffff888091c4eb30 EFLAGS: 00010282
RAX: 0000000000000083 RBX: ffff8880a2c5c200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff814dff01 RDI: ffffed1012389d58
RBP: ffffffff894c58c0 R08: 0000000000000083 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffffffff86eec28f
R13: 0000000000000008 R14: ffff8880b0566700 R15: 00000000000000c0
FS:  00005555558d8300(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009bb95000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400