skb linear: 00000040: 00 00 00 00 00 00 26 00 00 00 0c 00 99 00 00 00 skb linear: 00000050: 00 00 dc 88 00 00 04 00 af 00 00 00 23 77 00 00 skb linear: 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 skb linear: 00000070: 00 00 00 00 skb frag: 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 ------------[ cut here ]------------ offset+2 (553) > skb_headlen() (116) WARNING: CPU: 1 PID: 5057 at net/core/dev.c:3302 skb_checksum_help+0x5f1/0x750 net/core/dev.c:3302 Modules linked in: CPU: 1 PID: 5057 Comm: syz-executor608 Not tainted 6.8.0-rc2-syzkaller-00251-g6897cea71837 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0010:skb_checksum_help+0x5f1/0x750 net/core/dev.c:3302 Code: 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 52 01 00 00 44 89 e2 2b 53 74 4c 89 ee 48 c7 c7 60 a8 2b 8c e8 70 63 a8 f8 90 <0f> 0b 90 90 e9 87 fe ff ff e8 11 5d 3d f9 e9 3c fa ff ff e8 37 5d RSP: 0018:ffffc9000335f0a8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88807a6208c0 RCX: ffffffff814f7499 RDX: ffff888027ba0000 RSI: ffffffff814f74a6 RDI: 0000000000000001 RBP: ffff88807a620934 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000080 R13: 0000000000000229 R14: ffff88807a620930 R15: 0000000000000227 FS: 0000555556846380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002000d000 CR3: 000000006a9c8000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip_do_fragment+0xa1c/0x18b0 net/ipv4/ip_output.c:777 ip_fragment.constprop.0+0x161/0x230 net/ipv4/ip_output.c:584 ip_finish_output_gso net/ipv4/ip_output.c:286 [inline] __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x5af/0x950 net/ipv4/ip_output.c:295 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:323 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_mc_output+0x1dd/0x6a0 net/ipv4/ip_output.c:420 dst_output include/net/dst.h:451 [inline] dst_output include/net/dst.h:449 [inline] ip_local_out+0x286/0x4a0 net/ipv4/ip_output.c:129 iptunnel_xmit+0x5b4/0x9b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1dbc/0x33d0 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x49b/0x980 net/ipv4/ip_gre.c:665 __netdev_start_xmit include/linux/netdevice.h:4989 [inline] netdev_start_xmit include/linux/netdevice.h:5003 [inline] xmit_one net/core/dev.c:3547 [inline] dev_hard_start_xmit+0x13a/0x6d0 net/core/dev.c:3563 __dev_queue_xmit+0x7b6/0x3ee0 net/core/dev.c:4351 dev_queue_xmit include/linux/netdevice.h:3171 [inline] packet_xmit+0x23e/0x360 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3081 [inline] packet_sendmsg+0x24aa/0x51f0 net/packet/af_packet.c:3113 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0xab5/0xc90 net/socket.c:2584 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2638 __sys_sendmsg+0x117/0x1f0 net/socket.c:2667 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7fd67dc075d9 Code: 48 83 c4 28 c3 e8 d7 19 00 00 0f 1f 80 00 00 00 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:00007fff5544efe8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd67dc075d9 RDX: 0000000000000000 RSI: 0000000020002ac0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000555500000000 R10: 0000000000000004 R11: 0000000000000246 R12: 00007fff5544f030 R13: 00007fff5544f000 R14: 0000000000000001 R15: 00007fff5544f030