------------[ cut here ]------------
WARNING: CPU: 0 PID: 18571 at include/linux/skbuff.h:2796 skb_mac_header_len include/linux/skbuff.h:2796 [inline]
WARNING: CPU: 0 PID: 18571 at include/linux/skbuff.h:2796 skb_tunnel_check_pmtu+0x5de/0x2f90 net/ipv4/ip_tunnel_core.c:413
Modules linked in:
CPU: 0 PID: 18571 Comm: syz-executor.3 Not tainted 5.19.0-rc4-next-20220627-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:skb_mac_header_len include/linux/skbuff.h:2796 [inline]
RIP: 0010:skb_tunnel_check_pmtu+0x5de/0x2f90 net/ipv4/ip_tunnel_core.c:413
Code: 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 80 3c 02 00 0f 84 b9 fe ff ff 4c 89 ff e8 8c ed d4 f9 e9 ac fe ff ff e8 82 e6 88 f9 <0f> 0b e9 28 fc ff ff e8 76 e6 88 f9 48 8b 54 24 70 48 b8 00 00 00
RSP: 0018:ffffc9000c1b7700 EFLAGS: 00010216
RAX: 000000000000028c RBX: ffff888071631280 RCX: ffffc9000be34000
RDX: 0000000000040000 RSI: ffffffff87f1d07e RDI: 0000000000000003
RBP: ffffc9000c1b7828 R08: 0000000000000003 R09: 000000000000ffff
R10: 000000000000ffff R11: 0000000000000000 R12: 000000000000ffff
R13: 0000000000000000 R14: 000000000000ffcd R15: 000000000000000e
FS:  00007f731d52f700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e521000 CR3: 0000000038588000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 geneve_xmit_skb drivers/net/geneve.c:927 [inline]
 geneve_xmit+0xd9a/0x35c0 drivers/net/geneve.c:1107
 __netdev_start_xmit include/linux/netdevice.h:4805 [inline]
 netdev_start_xmit include/linux/netdevice.h:4819 [inline]
 __dev_direct_xmit+0x500/0x730 net/core/dev.c:4311
 dev_direct_xmit include/linux/netdevice.h:3007 [inline]
 packet_direct_xmit+0x1b3/0x2c0 net/packet/af_packet.c:282
 packet_snd net/packet/af_packet.c:3073 [inline]
 packet_sendmsg+0x21c6/0x5580 net/packet/af_packet.c:3104
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:734
 __sys_sendto+0x21a/0x320 net/socket.c:2116
 __do_sys_sendto net/socket.c:2128 [inline]
 __se_sys_sendto net/socket.c:2124 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2124
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f731c489109
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f731d52f168 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f731c59bf60 RCX: 00007f731c489109
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f731c4e305d R08: 0000000020000000 R09: 0000000000000014
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd329f8b8f R14: 00007f731d52f300 R15: 0000000000022000
 </TASK>