skbuff: skb_under_panic: text:00000000ec9727bb len:30 put:24 head:0000000099d53efb data:000000008f5346d2 tail:0x6 end:0xc0 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: 761 Comm: syz-executor5 Not tainted 4.15.0-rc8+ #205
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:ffff8801ceccf9f8 EFLAGS: 00010282
RAX: 0000000000000083 RBX: ffff8801d42b0980 RCX: 0000000000000000
RDX: 0000000000000083 RSI: ffffc90004849000 RDI: ffffed0039d99f33
RBP: ffff8801ceccfa60 R08: 1ffff10039d99ec1 R09: 0000000000000000
R10: ffff8801ceccf8a0 R11: 0000000000000000 R12: ffffffff861fb220
R13: ffffffff84a5f0ad R14: 0000000000000018 R15: ffff8801c2a0ed40
FS:  00007f4daf775700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000071c000 CR3: 00000001bd1d2001 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:00007f4daf774c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452f19
RDX: 0000000000000000 RSI: 000000002000bfc4 RDI: 0000000000000013
RBP: 0000000000000063 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ef9e8
R13: 00000000ffffffff R14: 00007f4daf7756d4 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 66 e2 26 fd <0f> 0b 4c 89 4d b8 4c 89 45 c0 48 89 75 c8 48 89 55 d0 e8 87 3a 
RIP: skb_panic+0x162/0x1f0 net/core/skbuff.c:100 RSP: ffff8801ceccf9f8
---[ end trace f1b5db83f42a44d1 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..