kernel BUG at include/linux/skbuff.h:LINE!

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 17529385 Linux 4.14.213
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=102e8998d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f94010bb59bd4675
dashboard link: https://syzkaller.appspot.com/bug?extid=18efe83d139c3ace5c78
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12a967c0d00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17429d57500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+18efe8...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
batman_adv: batadv0: Interface activated: batadv_slave_1
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready
------------[ cut here ]------------
kernel BUG at include/linux/skbuff.h:2133!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 8217 Comm: syz-executor776 Not tainted 4.14.213-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880afeb2600 task.stack: ffff8880b4eb8000
RIP: 0010:__skb_pull include/linux/skbuff.h:2133 [inline]
RIP: 0010:skb_pull_inline include/linux/skbuff.h:2139 [inline]
RIP: 0010:skb_pull net/core/skbuff.c:1735 [inline]
RIP: 0010:skb_pull+0xe1/0x100 net/core/skbuff.c:1733
RSP: 0018:ffff8880b4ebf518 EFLAGS: 00010297
RAX: ffff8880afeb2600 RBX: ffff88809c4ebdc0 RCX: 00000000000000a0
RDX: 0000000000000000 RSI: 0000000000000018 RDI: ffff88809c4ebe44
RBP: 0000000000000018 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: ffff8880afeb2600 R12: 0000000000000fde
R13: ffff88809d3c70c0 R14: ffff88809d3c7160 R15: ffff88809c4ebe98
FS: 00007effac529700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000040 CR3: 000000009f7a2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ipgre_xmit+0x26d/0x6d0 net/ipv4/ip_gre.c:658
__netdev_start_xmit include/linux/netdevice.h:4039 [inline]
netdev_start_xmit include/linux/netdevice.h:4048 [inline]
xmit_one net/core/dev.c:3005 [inline]
dev_hard_start_xmit+0x188/0x890 net/core/dev.c:3021
__dev_queue_xmit+0x1d7f/0x2480 net/core/dev.c:3521
packet_snd+0x1393/0x21e0 net/packet/af_packet.c:3024
packet_sendmsg+0x1139/0x2aca net/packet/af_packet.c:3049
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xb5/0x100 net/socket.c:656
sock_no_sendpage+0xe2/0x110 net/core/sock.c:2595
kernel_sendpage net/socket.c:3407 [inline]
sock_sendpage+0xdf/0x140 net/socket.c:871
pipe_to_sendpage+0x226/0x2d0 fs/splice.c:451
splice_from_pipe_feed fs/splice.c:502 [inline]
__splice_from_pipe+0x326/0x7a0 fs/splice.c:626
splice_from_pipe fs/splice.c:661 [inline]
generic_splice_sendpage+0xc1/0x110 fs/splice.c:832
do_splice_from fs/splice.c:851 [inline]
do_splice fs/splice.c:1147 [inline]
SYSC_splice fs/splice.c:1402 [inline]
SyS_splice+0xd59/0x1380 fs/splice.c:1382
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x448de9
RSP: 002b:00007effac528d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00000000006dec78 RCX: 0000000000448de9
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00000000006dec70 R08: 000000000004ffe0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dec7c
R13: 0000000000000000 R14: 0000000030657267 R15: 00000000006dec7c
Code: 00 00 4c 89 a3 d8 00 00 00 e8 8c 86 7d fb 4c 89 e0 5b 5d 41 5c c3 e8 7f 86 7d fb 45 31 e4 5b 4c 89 e0 5d 41 5c c3 e8 6f 86 7d fb <0f> 0b e8 58 56 a7 fb e9 49 ff ff ff e8 4e 56 a7 fb eb 8e e8 b7
RIP: __skb_pull include/linux/skbuff.h:2133 [inline] RSP: ffff8880b4ebf518
RIP: skb_pull_inline include/linux/skbuff.h:2139 [inline] RSP: ffff8880b4ebf518
RIP: skb_pull net/core/skbuff.c:1735 [inline] RSP: ffff8880b4ebf518
RIP: skb_pull+0xe1/0x100 net/core/skbuff.c:1733 RSP: ffff8880b4ebf518
---[ end trace 06ddcbbb28c76911 ]---


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