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: 3 PID: 3795 Comm: syz-executor4 Not tainted 4.13.0-next-20170908+ #18
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88006778a1c0 task.stack: ffff880067790000
RIP: 0010:loop_set_fd drivers/block/loop.c:885 [inline]
RIP: 0010:lo_ioctl+0x678/0x1b80 drivers/block/loop.c:1353
RSP: 0018:ffff880067797aa0 EFLAGS: 00010202
RAX: 0000000000010000 RBX: dffffc0000000000 RCX: ffffc90003085000
RDX: 000000000000003b RSI: ffffffff83539418 RDI: 00000000000001d8
RBP: ffff880067797b18 R08: 0000000000000000 R09: 1ffff1000cef2efd
R10: ffff88006778a1c0 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88006b63a480 R14: ffff88003e470040 R15: ffff88006b63a5d8
FS:  00007fcc4611b700(0000) GS:ffff88006df00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001ddbc23000 CR3: 000000006db77000 CR4: 00000000000006e0
DR0: 0000000020000000 DR1: 0000000020001008 DR2: 0000000020001000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0xc07/0x1de0 block/ioctl.c:594
 block_ioctl+0xea/0x130 fs/block_dev.c:1870
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1530 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: 0033:0x447299
RSP: 002b:00007fcc4611ac08 EFLAGS: 00000296 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000016 RCX: 0000000000447299
RDX: 0000000000000005 RSI: 0000000000004c00 RDI: 0000000000000016
RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 00000000ffffffff
R13: 0000000000006060 R14: 00000000006e9120 R15: 0000000020682000
Code: 00 00 00 48 89 fa 48 c1 ea 03 80 3c 1a 00 0f 85 81 14 00 00 4d 8b a4 24 f0 00 00 00 49 8d bc 24 d8 01 00 00 48 89 fa 48 c1 ea 03 <80> 3c 1a 00 0f 85 56 14 00 00 4d 8b a4 24 d8 01 00 00 4c 89 e2 
RIP: loop_set_fd drivers/block/loop.c:885 [inline] RSP: ffff880067797aa0
RIP: lo_ioctl+0x678/0x1b80 drivers/block/loop.c:1353 RSP: ffff880067797aa0
---[ end trace 5e5a35bc1b487670 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..