skbuff: skb_under_panic: text:00000000dddd2266 len:1488 put:24 head:00000000c816eb2f data:000000008752b32e 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: 0 PID: 31065 Comm: syz-executor3 Not tainted 4.15.0-rc9+ #206
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:ffff88019e1e79f8 EFLAGS: 00010282
RAX: 0000000000000088 RBX: ffff8801d52b0040 RCX: 0000000000000000
RDX: 0000000000000088 RSI: ffffc90002923000 RDI: ffffed0033c3cf33
RBP: ffff88019e1e7a60 R08: 1ffff10033c3cec1 R09: 0000000000000000
R10: 00000000000000b7 R11: 0000000000000000 R12: ffffffff861fb220
R13: ffffffff84a5e53d R14: 0000000000000018 R15: ffff8801d853a280
FS:  00007fef929f0700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000071c000 CR3: 00000001b4566001 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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:879
 dev_hard_header include/linux/netdevice.h:2731 [inline]
 pppoe_sendmsg+0x58e/0x8b0 drivers/net/ppp/pppoe.c:890
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 sock_write_iter+0x31a/0x5d0 net/socket.c:909
 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: 0033:0x452f19
RSP: 002b:00007fef929efc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fef929f0700 RCX: 0000000000452f19
RDX: 00000000000005b2 RSI: 000000002000fffe RDI: 0000000000000013
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a2f7cf R14: 00007fef929f09c0 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 aa 1f 86 52 56 4c 89 ea 41 50 4c 89 e6 45 89 f0 e8 06 f3 26 fd <0f> 0b 4c 89 4d b8 4c 89 45 c0 48 89 75 c8 48 89 55 d0 e8 47 44 
RIP: skb_panic+0x162/0x1f0 net/core/skbuff.c:100 RSP: ffff88019e1e79f8
---[ end trace 26881643442f0c93 ]---
netlink: 3 bytes leftover after parsing attributes in process `syz-executor7'.
netlink: 3 bytes leftover after parsing attributes in process `syz-executor7'.
netlink: 3 bytes leftover after parsing attributes in process `syz-executor7'.