TITLE: kernel BUG in ipgre_header
TYPE: BUG

[   34.354336] skbuff: skb_under_panic: text:000000000470095b len:82 put:24 head:00000000f453c8df data:000000007cc2256c tail:0x3a end:0xc0 dev:gre0
[   34.367572] ------------[ cut here ]------------
[   34.372298] kernel BUG at net/core/skbuff.c:104!
[   34.377065] invalid opcode: 0000 [#1] SMP KASAN
[   34.381704] Dumping ftrace buffer:
[   34.385210]    (ftrace buffer empty)
[   34.388893] Modules linked in:
[   34.392058] CPU: 0 PID: 3648 Comm: syzkaller888153 Not tainted 4.15.0-rc8+ #263
[   34.399497] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   34.408828] RIP: 0010:skb_panic+0x162/0x1f0
[   34.413116] RSP: 0018:ffff8801bc95f840 EFLAGS: 00010282
[   34.418448] RAX: 0000000000000084 RBX: ffff8801d4c40800 RCX: 0000000000000000
[   34.425688] RDX: 0000000000000084 RSI: 1ffff1003792bec8 RDI: ffffed003792befc
[   34.432930] RBP: ffff8801bc95f8a8 R08: 1ffff1003792be8a R09: 0000000000000000
[   34.440167] R10: 0000000000000008 R11: 0000000000000000 R12: ffffffff861f8fe0
[   34.447407] R13: ffffffff84a31e3d R14: 0000000000000018 R15: ffff8801d31ae0c0
[   34.454650] FS:  000000000251d880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
[   34.462842] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   34.468694] CR2: 0000000020fa3000 CR3: 00000001d94ef006 CR4: 00000000001606f0
[   34.475937] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   34.483177] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   34.490414] Call Trace:
[   34.501306]  skb_push+0xce/0xf0
[   34.504562]  ipgre_header+0x6d/0x4e0
[   34.508249]  pppoe_sendmsg+0x58e/0x8b0
[   34.534161]  sock_sendmsg+0xca/0x110
[   34.537847]  sock_write_iter+0x31a/0x5d0
[   34.553801]  do_iter_readv_writev+0x525/0x7f0
[   34.567027]  do_iter_write+0x154/0x540
[   34.574489]  vfs_writev+0x18a/0x340
[   34.605550]  do_writev+0xfc/0x2a0
[   34.626153]  SyS_writev+0x27/0x30
[   34.629593]  entry_SYSCALL_64_fastpath+0x29/0xa0
[   34.634326] RIP: 0033:0x445109
[   34.637486] RSP: 002b:00007fff3b81d8d8 EFLAGS: 00000217 ORIG_RAX: 0000000000000014
[   34.645161] RAX: ffffffffffffffda RBX: 00000000004a6952 RCX: 0000000000445109
[   34.652400] RDX: 0000000000000006 RSI: 0000000020935fa0 RDI: 0000000000000004
[   34.659637] RBP: 00007fff3b81d9d8 R08: 0000000020ae0000 R09: 0000000020ae0000
[   34.666878] R10: 0000000020ae0000 R11: 0000000000000217 R12: 00007fff3b81d9d8
[   34.674116] R13: 0000000000402610 R14: 0000000000000000 R15: 0000000000000000
[   34.681362] Code: 04 01 84 c0 74 04 3c 03 7e 23 8b 8b 80 00 00 00 41 57 48 c7 c7 a0 88 1f 86 52 56 4c 89 ea 41 50 4c 89 e6 45 89 f0 e8 b6 bd 28 fd <0f> 0b 4c 89 4d b8 4c 89 45 c0 48 89 75 c8 48 89 55 d0 e8 f7 09 
[   34.700425] RIP: skb_panic+0x162/0x1f0 RSP: ffff8801bc95f840
[   34.706348] ---[ end trace 0b1fd34e17500035 ]---
