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: 2 PID: 8143 Comm: syz-executor0 Not tainted 4.13.0-rc5-next-20170817+ #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff880056f0a0c0 task.stack: ffff880069088000
RIP: 0010:loop_set_fd drivers/block/loop.c:910 [inline]
RIP: 0010:lo_ioctl+0x5df/0x1700 drivers/block/loop.c:1378
RSP: 0018:ffff88006908fa98 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90001106000
RDX: 0000000000000054 RSI: ffffffff8352457f RDI: 00000000000001b8
RBP: ffff88006908fb18 R08: 0000000000000000 R09: 1ffff1000d211f04
R10: ffff88006908f7e8 R11: ffffffff85b34400 R12: 0000000000000000
R13: ffff880069959680 R14: ffff88003cbae480 R15: ffff88003cbae5d8
FS:  00007fa5fadf4700(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000056dbe000 CR4: 00000000000026e0
Call Trace:
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0xc07/0x1de0 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1867
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x446749
RSP: 002b:00007fa5fadf3c08 EFLAGS: 00000282 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000016 RCX: 0000000000446749
RDX: 0000000000000005 RSI: 0000000000004c00 RDI: 0000000000000016
RBP: 0000000000708000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000282 R12: 00000000ffffffff
R13: 00000000000056b0 R14: 00000000006e7770 R15: fffffffffffffffd
Code: 00 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 bd 10 00 00 4d 8b a4 24 f0 00 00 00 49 8d bc 24 b8 01 00 00 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 b3 10 00 00 4d 8b a4 24 b8 01 00 00 4c 89 e0 
RIP: loop_set_fd drivers/block/loop.c:910 [inline] RSP: ffff88006908fa98
RIP: lo_ioctl+0x5df/0x1700 drivers/block/loop.c:1378 RSP: ffff88006908fa98
---[ end trace 5f35c462fa8bcf93 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..