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: 1 PID: 13734 Comm: syz-executor3 Not tainted 4.13.0-rc5-next-20170815+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88005c2543c0 task.stack: ffff880059a80000
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:ffff880059a86f20 EFLAGS: 00010a02
RAX: 10db6edb8443a9b3 RBX: dffffc0000000000 RCX: ffffc90001147000
RDX: 0000000000010000 RSI: ffffffff83dff427 RDI: 86db76dc221d4d98
RBP: ffff880059a87040 R08: ffffea0000baefa0 R09: ffffed0007ab8c00
R10: 0000000000028c28 R11: 0000000000000010 R12: ffff880059dc81f0
R13: ffffed000b350dfb R14: 1ffff1000b350df3 R15: 86db76dc221d4d78
FS:  00007f0d34149700(0000) GS:ffff88003ed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000204ad000 CR3: 000000003ab57000 CR4: 00000000000026e0
DR0: 0000000020001010 DR1: 0000000020000008 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
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
 __netif_receive_skb_core+0x10f8/0x33d0 net/core/dev.c:4425
 __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: 0033:0x40bab1
RSP: 002b:00007f0d34148c00 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000055 RCX: 000000000040bab1
RDX: 0000000000000055 RSI: 0000000020014fab RDI: 0000000000000015
RBP: 0000000000708000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff
R13: 0000000000004e80 R14: 00000000006e6f40 R15: 0000000000000006
Code: c6 e8 c9 78 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: ffff880059a86f20
RIP: compound_head include/linux/page-flags.h:146 [inline] RSP: ffff880059a86f20
RIP: put_page include/linux/mm.h:811 [inline] RSP: ffff880059a86f20
RIP: __skb_frag_unref include/linux/skbuff.h:2743 [inline] RSP: ffff880059a86f20
RIP: skb_release_data+0x26c/0x790 net/core/skbuff.c:568 RSP: ffff880059a86f20
---[ end trace 85e2b29302515a8c ]---