------------[ cut here ]------------ WARNING: CPU: 0 PID: 6229 at net/core/dev.c:3263 skb_checksum_help+0x3b5/0x560 Modules linked in: CPU: 0 PID: 6229 Comm: syz.1.607 Not tainted 5.15.161-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 RIP: 0010:skb_checksum_help+0x3b5/0x560 net/core/dev.c:3263 Code: 5e 41 5f 5d c3 e8 6b 8b 4a f9 bb f4 ff ff ff eb e3 e8 5f 8b 4a f9 4c 89 ff e8 b7 01 00 00 bb ea ff ff ff eb cf e8 4b 8b 4a f9 <0f> 0b bb ea ff ff ff eb c1 e8 3d 8b 4a f9 0f 0b bb ea ff ff ff eb RSP: 0018:ffffc900030f6ec8 EFLAGS: 00010283 RAX: ffffffff8835cf85 RBX: 0000000000002989 RCX: 0000000000040000 RDX: ffffc90003ed1000 RSI: 00000000000037d2 RDI: 00000000000037d3 RBP: 0000000000002989 R08: ffffffff8835cdf8 R09: ffffc900030f7060 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000002989 R13: ffff88806811f430 R14: 1ffff1100d023e86 R15: ffff88806811f3c0 FS: 00007fd8f78db6c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002000e000 CR3: 0000000069dfc000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip_do_fragment+0x1cf/0x1f10 net/ipv4/ip_output.c:774 iptunnel_xmit+0x513/0x950 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x198c/0x27b0 net/ipv4/ip_tunnel.c:837 __gre_xmit net/ipv4/ip_gre.c:474 [inline] ipgre_xmit+0x81c/0xbf0 net/ipv4/ip_gre.c:669 __netdev_start_xmit include/linux/netdevice.h:5019 [inline] netdev_start_xmit include/linux/netdevice.h:5033 [inline] xmit_one net/core/dev.c:3617 [inline] dev_hard_start_xmit+0x298/0x7a0 net/core/dev.c:3633 __dev_queue_xmit+0x1cee/0x3230 net/core/dev.c:4248 packet_snd net/packet/af_packet.c:3038 [inline] packet_sendmsg+0x449d/0x5e90 net/packet/af_packet.c:3069 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485 __sys_sendmsg net/socket.c:2514 [inline] __do_sys_sendmsg net/socket.c:2523 [inline] __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fd8f8e5ab99 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:00007fd8f78db048 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fd8f8fe8fa0 RCX: 00007fd8f8e5ab99 RDX: 0000000000000000 RSI: 0000000020002ac0 RDI: 0000000000000004 RBP: 00007fd8f8edb77e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fd8f8fe8fa0 R15: 00007ffe05f96118