------------[ 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: 18751 Comm: syz-executor5 Not tainted 4.15.0-rc7+ #168
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:ffff8801c22070e0 EFLAGS: 00010212
RAX: 0000000000010000 RBX: ffff8801ca4cfa00 RCX: ffffffff842f2118
RDX: 00000000000001a2 RSI: ffffc90003c66000 RDI: ffff8801ca4cfa84
RBP: ffff8801c22070f8 R08: 1ffff10038440d85 R09: 0000000000000002
R10: ffff8801c22070e8 R11: 0000000000000000 R12: 0000000000000028
R13: 0000000000000028 R14: dffffc0000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:00000000f7749b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000009bc21000 CR3: 00000001d3ba7004 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
 compat_writev+0x225/0x420 fs/read_write.c:1246
 do_compat_writev+0x115/0x220 fs/read_write.c:1267
 C_SYSC_writev fs/read_write.c:1278 [inline]
 compat_SyS_writev+0x26/0x30 fs/read_write.c:1274
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f4dc79
RSP: 002b:00000000f7749014 EFLAGS: 00000296 ORIG_RAX: 0000000000000092
RAX: ffffffffffffffda RBX: 0000000000000012 RCX: 00000000f7749064
RDX: 0000000000000002 RSI: 0000000000000586 RDI: 00000000f7749b28
RBP: 00000000081102c8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 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: ffff8801c22070e0
RIP: skb_pull_inline include/linux/skbuff.h:2074 [inline] RSP: ffff8801c22070e0
RIP: skb_pull+0xe8/0x110 net/core/skbuff.c:1731 RSP: ffff8801c22070e0
---[ end trace 941948b2e773bd8d ]---