skb linear:   000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
skb linear:   000000e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
skb linear:   000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
skb linear:   00000100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
skb linear:   00000110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
skb linear:   00000120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
------------[ cut here ]------------
offset+2 (34985) > skb_headlen() (1639)
WARNING: CPU: 1 PID: 7406 at net/core/dev.c:3336 skb_checksum_help+0x68f/0x730 net/core/dev.c:3335
Modules linked in:
CPU: 1 PID: 7406 Comm: syz.4.769 Not tainted 6.10.0-rc6-syzkaller-01403-g40ab9e0dc865 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:skb_checksum_help+0x68f/0x730 net/core/dev.c:3335
Code: 48 8b 4c 24 10 0f b6 04 01 84 c0 0f 85 89 00 00 00 48 8b 44 24 08 2b 18 48 c7 c7 c0 88 c5 8c 4c 89 f6 89 da e8 e2 fd ff f7 90 <0f> 0b 90 90 bb ea ff ff ff e9 cf fc ff ff 48 8b 0c 24 80 e1 07 80
RSP: 0018:ffffc90003366b68 EFLAGS: 00010246
RAX: d6ded7cda7944400 RBX: 0000000000000667 RCX: 0000000000040000
RDX: ffffc90009e61000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: dffffc0000000000 R08: ffffffff81585752 R09: 1ffff9200066cd0c
R10: dffffc0000000000 R11: fffff5200066cd0d R12: 1ffff1100d3cff76
R13: 00000000000088a7 R14: 00000000000088a9 R15: ffff888069e7fb40
FS:  00007f32504a76c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000d000 CR3: 0000000063ee0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ip_do_fragment+0x20d/0x1b30 net/ipv4/ip_output.c:777
 iptunnel_xmit+0x540/0x9b0 net/ipv4/ip_tunnel_core.c:82
 ip_tunnel_xmit+0x2119/0x2950 net/ipv4/ip_tunnel.c:857
 __gre_xmit net/ipv4/ip_gre.c:483 [inline]
 ipgre_xmit+0x958/0xd40 net/ipv4/ip_gre.c:687
 __netdev_start_xmit include/linux/netdevice.h:4910 [inline]
 netdev_start_xmit include/linux/netdevice.h:4919 [inline]
 xmit_one net/core/dev.c:3580 [inline]
 dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3596
 sch_direct_xmit+0x2b6/0x5f0 net/sched/sch_generic.c:343
 qdisc_restart net/sched/sch_generic.c:408 [inline]
 __qdisc_run+0xbfd/0x2170 net/sched/sch_generic.c:416
 __dev_xmit_skb net/core/dev.c:3878 [inline]
 __dev_queue_xmit+0x1119/0x3e90 net/core/dev.c:4389
 packet_snd net/packet/af_packet.c:3079 [inline]
 packet_sendmsg+0x4bc0/0x6710 net/packet/af_packet.c:3111
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 ____sys_sendmsg+0x525/0x7d0 net/socket.c:2585
 ___sys_sendmsg net/socket.c:2639 [inline]
 __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f324f775bd9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f32504a7048 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f324f903f60 RCX: 00007f324f775bd9
RDX: 0000000000000000 RSI: 0000000020002ac0 RDI: 0000000000000004
RBP: 00007f324f7e4e60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f324f903f60 R15: 00007ffdd8e834d8
 </TASK>