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 (1639) >= skb_headlen() (1639) WARNING: CPU: 0 PID: 7701 at net/core/dev.c:3326 skb_checksum_help+0x536/0x750 net/core/dev.c:3326 Modules linked in: CPU: 0 PID: 7701 Comm: syz.0.914 Not tainted 6.10.0-syzkaller-04806-g8b0f0bb27c32 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:skb_checksum_help+0x536/0x750 net/core/dev.c:3326 Code: 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 00 02 00 00 44 89 e2 2b 53 74 44 89 ee 48 c7 c7 e0 3c 51 8c e8 4b 4b 92 f8 90 <0f> 0b 90 90 e9 42 ff ff ff e8 5c 9c cf f8 44 0f b6 25 ef 40 0e 07 RSP: 0018:ffffc900031d6f20 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff8880270a0640 RCX: ffffc90028dfb000 RDX: 0000000000040000 RSI: ffffffff81514706 RDI: 0000000000000001 RBP: ffff8880270a06b4 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000667 R13: 0000000000000667 R14: ffff8880270a06b0 R15: 000000000000070f FS: 0000000000000000(0000) GS:ffff88802c000000(0063) knlGS:00000000f5ce6b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 000000002000d000 CR3: 0000000000e6e000 CR4: 0000000000350ef0 Call Trace: ip_do_fragment+0xa1e/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_output+0x13b/0x2a0 net/ipv4/ip_output.c:433 dst_output include/net/dst.h:450 [inline] ip_local_out+0x33e/0x4a0 net/ipv4/ip_output.c:129 iptunnel_xmit+0x5b4/0x9c0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1e82/0x33f0 net/ipv4/ip_tunnel.c:857 __gre_xmit+0x89d/0xbd0 net/ipv4/ip_gre.c:483 ipgre_xmit+0x578/0xb30 net/ipv4/ip_gre.c:687 __netdev_start_xmit include/linux/netdevice.h:4913 [inline] netdev_start_xmit include/linux/netdevice.h:4922 [inline] xmit_one net/core/dev.c:3580 [inline] dev_hard_start_xmit+0x143/0x790 net/core/dev.c:3596 __dev_queue_xmit+0x7c7/0x4300 net/core/dev.c:4423 dev_queue_xmit include/linux/netdevice.h:3105 [inline] packet_xmit+0x23e/0x360 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3145 [inline] packet_sendmsg+0x267f/0x5390 net/packet/af_packet.c:3177 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9b4/0xb50 net/socket.c:2597 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2651 __sys_sendmsg+0x117/0x1f0 net/socket.c:2680 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf73ce579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f5ce657c EFLAGS: 00000292 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000280 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi