------------[ cut here ]------------ WARNING: CPU: 1 PID: 7077 at net/core/dev.c:3269 skb_checksum_help+0x3c3/0x560 Modules linked in: CPU: 1 PID: 7077 Comm: syz.1.802 Not tainted 5.15.164-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:skb_checksum_help+0x3c3/0x560 net/core/dev.c:3269 Code: ff eb e3 e8 cf fc 35 f9 4c 89 ff e8 b7 01 00 00 bb ea ff ff ff eb cf e8 bb fc 35 f9 0f 0b bb ea ff ff ff eb c1 e8 ad fc 35 f9 <0f> 0b bb ea ff ff ff eb b3 44 89 e1 80 e1 07 fe c1 38 c1 0f 8c 5f RSP: 0018:ffffc90003716cc8 EFLAGS: 00010287 RAX: ffffffff884a64b3 RBX: 0000000000003528 RCX: 0000000000040000 RDX: ffffc9000d802000 RSI: 000000000000c09f RDI: 000000000000c0a0 RBP: 000000000000296d R08: ffffffff884a63a2 R09: fffff520006e2d8a R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000090cc5d6d R13: ffff88807bb60070 R14: 1ffff1100f76c010 R15: ffff88807bb60000 FS: 00007f98a10636c0(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002000e000 CR3: 000000007cc9e000 CR4: 00000000003506e0 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 sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342 qdisc_restart net/sched/sch_generic.c:407 [inline] __qdisc_run+0xae2/0x1e90 net/sched/sch_generic.c:415 __dev_xmit_skb net/core/dev.c:3902 [inline] __dev_queue_xmit+0xf0a/0x3230 net/core/dev.c:4213 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: 0033:0x7f98a2be69f9 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:00007f98a1063038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f98a2d82f80 RCX: 00007f98a2be69f9 RDX: 0000000000000000 RSI: 0000000020002ac0 RDI: 0000000000000003 RBP: 00007f98a2c548ee R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f98a2d82f80 R15: 00007ffd515bc548