kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 3363 Comm: syz-executor1 Not tainted 4.13.0-rc5-next-20170816+ #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c7b4e380 task.stack: ffff8801c8238000
RIP: 0010:__read_once_size include/linux/compiler.h:276 [inline]
RIP: 0010:compound_head include/linux/page-flags.h:146 [inline]
RIP: 0010:put_page include/linux/mm.h:811 [inline]
RIP: 0010:__skb_frag_unref include/linux/skbuff.h:2743 [inline]
RIP: 0010:skb_release_data+0x26c/0x790 net/core/skbuff.c:568
RSP: 0018:ffff8801c823eda8 EFLAGS: 00010202
RAX: 0000000000000004 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff85b34bc0 RDI: 0000000000000020
RBP: ffff8801c823eec8 R08: ffff8801cdf26ec8 R09: 000060fe24a0d670
R10: ffff8801c823f6b0 R11: 0000000000000007 R12: ffff8801ce6481b0
R13: ffffed0039047dcc R14: 1ffff10039047dc4 R15: 0000000000000000
FS:  00007f6ddd2e6700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020004000 CR3: 00000001c7439000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_release_all+0x4a/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 kfree_skb+0x15d/0x4c0 net/core/skbuff.c:663
 ip_rcv+0x40a/0x17d0 net/ipv4/ip_input.c:497
 __netif_receive_skb_core+0x19af/0x33d0 net/core/dev.c:4418
 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4456
 netif_receive_skb_internal+0x10b/0x5e0 net/core/dev.c:4527
 netif_receive_skb+0xae/0x390 net/core/dev.c:4551
 tun_rx_batched.isra.43+0x5e7/0x860 drivers/net/tun.c:1221
 tun_get_user+0x11dd/0x2150 drivers/net/tun.c:1542
 tun_chr_write_iter+0xd8/0x190 drivers/net/tun.c:1568
 call_write_iter include/linux/fs.h:1742 [inline]
 new_sync_write fs/read_write.c:457 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:470
 vfs_write+0x189/0x510 fs/read_write.c:518
 SYSC_write fs/read_write.c:565 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:557
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x40b751
RSP: 002b:00007f6ddd2e5c10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 000000000040b751
RDX: 0000000000000036 RSI: 0000000020002000 RDI: 0000000000000003
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000f4246 R11: 0000000000000293 R12: 00000000004bab41
R13: 00000000ffffffff R14: 0000000020011000 R15: 0000000000000001
Code: c6 e8 c9 68 8d fd 4c 89 e0 48 c1 e8 03 80 3c 18 00 0f 85 93 04 00 00 4d 8b 3c 24 41 c6 45 00 00 49 8d 7f 20 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 6b 04 00 00 41 80 7d 00 00 49 8b 47 20 0f 85 
RIP: __read_once_size include/linux/compiler.h:276 [inline] RSP: ffff8801c823eda8
RIP: compound_head include/linux/page-flags.h:146 [inline] RSP: ffff8801c823eda8
RIP: put_page include/linux/mm.h:811 [inline] RSP: ffff8801c823eda8
RIP: __skb_frag_unref include/linux/skbuff.h:2743 [inline] RSP: ffff8801c823eda8
RIP: skb_release_data+0x26c/0x790 net/core/skbuff.c:568 RSP: ffff8801c823eda8
---[ end trace 26d5960c590f2106 ]---