------------[ cut here ]------------
kernel BUG at ./include/linux/skbuff.h:2068!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 7717 Comm: syz-executor3 Not tainted 4.15.0-rc7+ #259
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__skb_pull include/linux/skbuff.h:2068 [inline]
RIP: 0010:skb_pull_inline include/linux/skbuff.h:2074 [inline]
RIP: 0010:skb_pull+0xe8/0x110 net/core/skbuff.c:1731
RSP: 0018:ffff8801ccc77270 EFLAGS: 00010202
RAX: 0000000000010000 RBX: ffff8801cbc0bcc0 RCX: ffffffff842f2118
RDX: 00000000000001c0 RSI: ffffc90003ae7000 RDI: ffff8801cbc0bd44
RBP: ffff8801ccc77288 R08: 1ffff1003998edb7 R09: 0000000000000002
R10: ffff8801ccc77278 R11: 0000000000000000 R12: 0000000000000028
R13: 0000000000000024 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f95e5aa7700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020365efa CR3: 00000001d0860005 CR4: 00000000001606f0
Call Trace:
 esp6_gro_receive+0xb4/0xbe0 net/ipv6/esp6_offload.c:63
 call_gro_receive include/linux/netdevice.h:2200 [inline]
 ipv6_gro_receive+0x844/0x13e0 net/ipv6/ip6_offload.c:253
 dev_gro_receive+0xd38/0x2130 net/core/dev.c:4869
 napi_gro_frags+0x386/0xaf0 net/core/dev.c:5125
 tun_get_user+0x262e/0x3710 drivers/net/tun.c:1757
 tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1800
 call_write_iter include/linux/fs.h:1772 [inline]
 do_iter_readv_writev+0x525/0x7f0 fs/read_write.c:653
 do_iter_write+0x154/0x540 fs/read_write.c:932
 vfs_writev+0x18a/0x340 fs/read_write.c:977
 do_writev+0xfc/0x2a0 fs/read_write.c:1012
 SYSC_writev fs/read_write.c:1085 [inline]
 SyS_writev+0x27/0x30 fs/read_write.c:1082
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x4529a1
RSP: 002b:00007f95e5aa6b80 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 00000000004529a1
RDX: 0000000000000002 RSI: 00007f95e5aa6bd0 RDI: 0000000000000012
RBP: 00000000000003aa R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000005a R11: 0000000000000293 R12: 00000000006f3890
R13: 00000000ffffffff R14: 00007f95e5aa76d4 R15: 0000000000000000
Code: a3 d8 00 00 00 e8 89 f6 40 fd 4c 89 e0 5b 41 5c 41 5d 5d c3 45 31 e4 e8 77 f6 40 fd 4c 89 e0 5b 41 5c 41 5d 5d c3 e8 68 f6 40 fd <0f> 0b e8 11 f8 77 fd eb 97 e8 0a f8 77 fd e9 41 ff ff ff e8 20 
RIP: __skb_pull include/linux/skbuff.h:2068 [inline] RSP: ffff8801ccc77270
RIP: skb_pull_inline include/linux/skbuff.h:2074 [inline] RSP: ffff8801ccc77270
RIP: skb_pull+0xe8/0x110 net/core/skbuff.c:1731 RSP: ffff8801ccc77270
---[ end trace 87846840b47cb4ef ]---