skbuff: skb_under_panic: text:00000000d2e9a502 len:1488 put:24 head:0000000033d943dd data:00000000da5a2a70 tail:0x5b8 end:0x6c0 dev:gre0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:104!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 8461 Comm: syz-executor5 Not tainted 4.15.0-rc9+ #275
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:skb_panic+0x162/0x1f0 net/core/skbuff.c:100
RSP: 0018:ffff8801c4e4f9f8 EFLAGS: 00010282
RAX: 0000000000000088 RBX: ffff8801ce487d00 RCX: 0000000000000000
RDX: 0000000000000088 RSI: ffffc9000427d000 RDI: ffffed00389c9f33
RBP: ffff8801c4e4fa60 R08: 1ffff100389c9ec1 R09: 0000000000000000
R10: 00000000000000b7 R11: 0000000000000000 R12: ffffffff861f9a20
R13: ffffffff84a3818d R14: 0000000000000018 R15: ffff8801d46a6c00
FS:  00007f2a26421700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000071c000 CR3: 00000001bbcbc001 CR4: 00000000001606e0
Call Trace:
 skb_under_panic net/core/skbuff.c:114 [inline]
 skb_push+0xce/0xf0 net/core/skbuff.c:1714
 ipgre_header+0x6d/0x4e0 net/ipv4/ip_gre.c:877
 dev_hard_header include/linux/netdevice.h:2721 [inline]
 pppoe_sendmsg+0x58e/0x8b0 drivers/net/ppp/pppoe.c:890
 sock_sendmsg_nosec net/socket.c:638 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:648
 sock_write_iter+0x31a/0x5d0 net/socket.c:917
 call_write_iter include/linux/fs.h:1772 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452ef9
RSP: 002b:00007f2a26420c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2a26421700 RCX: 0000000000452ef9
RDX: 00000000000005b2 RSI: 000000002000fffe RDI: 0000000000000013
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a2f7cf R14: 00007f2a264219c0 R15: 0000000000000000
Code: 04 01 84 c0 74 04 3c 03 7e 23 8b 8b 80 00 00 00 41 57 48 c7 c7 e0 92 1f 86 52 56 4c 89 ea 41 50 4c 89 e6 45 89 f0 e8 86 6e 28 fd <0f> 0b 4c 89 4d b8 4c 89 45 c0 48 89 75 c8 48 89 55 d0 e8 67 bc 
RIP: skb_panic+0x162/0x1f0 net/core/skbuff.c:100 RSP: ffff8801c4e4f9f8
---[ end trace ba3442141b574e39 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..