skbuff: skb_under_panic: text:ffffffff87b8955f len:48 put:8 head:ffff8880352e4c00 data:ffff8880352e4bfc tail:0x2c end:0xc0 dev:sit1 ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:111! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1390 Comm: syz-executor.4 Not tainted 5.14.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:111 Code: f8 4c 8b 4c 24 10 8b 4b 70 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 e0 5f 8a 8a ff 74 24 10 ff 74 24 20 e8 09 58 c3 ff <0f> 0b e8 18 6d 4c f8 4c 8b 64 24 18 e8 2e fc 92 f8 48 c7 c1 80 6c RSP: 0018:ffffc900024f6b28 EFLAGS: 00010282 RAX: 0000000000000083 RBX: ffff8880121b7000 RCX: 0000000000000000 RDX: 0000000000040000 RSI: ffffffff815d87b5 RDI: fffff5200049ed57 RBP: ffffffff8a8a6c80 R08: 0000000000000083 R09: 0000000000000000 R10: ffffffff815d25ee R11: 0000000000000000 R12: ffffffff87b8955f R13: 0000000000000008 R14: ffff88801d114000 R15: 00000000000000c0 FS: 00007f863e598700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f863e598718 CR3: 0000000017cc9000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_under_panic net/core/skbuff.c:121 [inline] skb_push.cold+0x24/0x24 net/core/skbuff.c:1999 fou_build_udp+0x2f/0x350 net/ipv4/fou.c:1067 gue_build_header+0xf7/0x140 net/ipv4/fou.c:1110 ip_tunnel_encap include/net/ip_tunnels.h:370 [inline] ip_tunnel_xmit+0x5d3/0x2b60 net/ipv4/ip_tunnel.c:732 sit_tunnel_xmit__ net/ipv6/sit.c:1065 [inline] sit_tunnel_xmit+0x4fd/0x2aa0 net/ipv6/sit.c:1081 __netdev_start_xmit include/linux/netdevice.h:4961 [inline] netdev_start_xmit include/linux/netdevice.h:4975 [inline] xmit_one net/core/dev.c:3576 [inline] dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3592 __dev_queue_xmit+0x2a4d/0x3710 net/core/dev.c:4202 neigh_connected_output+0x3b6/0x510 net/core/neighbour.c:1521 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x813/0x2140 net/ipv4/ip_output.c:221 __ip_finish_output net/ipv4/ip_output.c:299 [inline] __ip_finish_output+0x396/0x640 net/ipv4/ip_output.c:281 ip_finish_output+0x32/0x200 net/ipv4/ip_output.c:309 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x196/0x310 net/ipv4/ip_output.c:423 dst_output include/net/dst.h:450 [inline] ip_local_out net/ipv4/ip_output.c:126 [inline] ip_send_skb+0xd4/0x260 net/ipv4/ip_output.c:1564 udp_send_skb+0x6cd/0x11a0 net/ipv4/udp.c:966 udp_sendmsg+0x1bad/0x2740 net/ipv4/udp.c:1253 udpv6_sendmsg+0x14f6/0x2c40 net/ipv6/udp.c:1359 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:643 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x331/0x810 net/socket.c:2403 ___sys_sendmsg+0xf3/0x170 net/socket.c:2457 __sys_sendmmsg+0x195/0x470 net/socket.c:2543 __do_sys_sendmmsg net/socket.c:2572 [inline] __se_sys_sendmmsg net/socket.c:2569 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2569 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665e9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f863e598188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9 RDX: 0000000000000001 RSI: 00000000200017c0 RDI: 0000000000000003 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038 R13: 00007ffc628f09ef R14: 00007f863e598300 R15: 0000000000022000 Modules linked in: ---[ end trace 617819d2dadb06a0 ]--- RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:111 Code: f8 4c 8b 4c 24 10 8b 4b 70 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 e0 5f 8a 8a ff 74 24 10 ff 74 24 20 e8 09 58 c3 ff <0f> 0b e8 18 6d 4c f8 4c 8b 64 24 18 e8 2e fc 92 f8 48 c7 c1 80 6c RSP: 0018:ffffc900024f6b28 EFLAGS: 00010282 RAX: 0000000000000083 RBX: ffff8880121b7000 RCX: 0000000000000000 RDX: 0000000000040000 RSI: ffffffff815d87b5 RDI: fffff5200049ed57 RBP: ffffffff8a8a6c80 R08: 0000000000000083 R09: 0000000000000000 R10: ffffffff815d25ee R11: 0000000000000000 R12: ffffffff87b8955f R13: 0000000000000008 R14: ffff88801d114000 R15: 00000000000000c0 FS: 00007f863e598700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f863e598718 CR3: 0000000017cc9000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: f8 clc 1: 4c 8b 4c 24 10 mov 0x10(%rsp),%r9 6: 8b 4b 70 mov 0x70(%rbx),%ecx 9: 41 56 push %r14 b: 45 89 e8 mov %r13d,%r8d e: 4c 89 e2 mov %r12,%rdx 11: 41 57 push %r15 13: 48 89 ee mov %rbp,%rsi 16: 48 c7 c7 e0 5f 8a 8a mov $0xffffffff8a8a5fe0,%rdi 1d: ff 74 24 10 pushq 0x10(%rsp) 21: ff 74 24 20 pushq 0x20(%rsp) 25: e8 09 58 c3 ff callq 0xffc35833 2a: 0f 0b ud2 <-- trapping instruction 2c: e8 18 6d 4c f8 callq 0xf84c6d49 31: 4c 8b 64 24 18 mov 0x18(%rsp),%r12 36: e8 2e fc 92 f8 callq 0xf892fc69 3b: 48 rex.W 3c: c7 .byte 0xc7 3d: c1 .byte 0xc1 3e: 80 .byte 0x80 3f: 6c insb (%dx),%es:(%rdi)