kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 16508 Comm: syz-executor1 Not tainted 4.4.154+ #96
task: ffff880096385f00 task.stack: ffff8800a5d58000
RIP: 0010:[<ffffffff81cd87e8>]  [<ffffffff81cd87e8>] is_loop_device drivers/block/loop.c:656 [inline]
RIP: 0010:[<ffffffff81cd87e8>]  [<ffffffff81cd87e8>] loop_validate_file+0x208/0x400 drivers/block/loop.c:667
RSP: 0018:ffff8800a5d5fb70  EFLAGS: 00010206
RAX: 0000000000000036 RBX: dffffc0000000000 RCX: ffffc90004cd5000
RDX: 000000000000008d RSI: ffffffff81cd87b8 RDI: 00000000000001b0
RBP: ffff8800a5d5fb88 R08: ffff8800963867c8 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8800b7d90b80 R14: ffff8800b7d90b80 R15: ffff8801d82ae558
FS:  00007f4635a97700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004df600 CR3: 00000001adb32000 CR4: 00000000001606b0
Stack:
 ffff8801d82ae400 ffff8801b191e600 0000000000000004 ffff8800a5d5fc18
 ffffffff81ce1d0d 1ffff10014babf78 0000002f00000006 0000000000000000
 00000001000000cf ffff8801d82ae418 0000000041b58ab3 ffffffff82c5aac0
Call Trace:
 [<ffffffff81ce1d0d>] loop_change_fd drivers/block/loop.c:713 [inline]
 [<ffffffff81ce1d0d>] lo_ioctl+0x3ed/0x16b0 drivers/block/loop.c:1370
 [<ffffffff81a23326>] __blkdev_driver_ioctl block/ioctl.c:288 [inline]
 [<ffffffff81a23326>] blkdev_ioctl+0x7a6/0x19a0 block/ioctl.c:584
 [<ffffffff81525dfe>] block_ioctl+0xde/0x120 fs/block_dev.c:1625
 [<ffffffff814acdaf>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff814acdaf>] file_ioctl fs/ioctl.c:470 [inline]
 [<ffffffff814acdaf>] do_vfs_ioctl+0x63f/0xf40 fs/ioctl.c:605
 [<ffffffff814ad73f>] SYSC_ioctl fs/ioctl.c:622 [inline]
 [<ffffffff814ad73f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
 [<ffffffff82690521>] entry_SYSCALL_64_fastpath+0x1e/0x9a
Code: 00 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 f7 01 00 00 4d 8b a4 24 f0 00 00 00 49 8d bc 24 b0 01 00 00 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 cc 01 00 00 4d 8b a4 24 b0 01 00 00 4c 89 e0 
RIP  [<ffffffff81cd87e8>] is_loop_device drivers/block/loop.c:656 [inline]
RIP  [<ffffffff81cd87e8>] loop_validate_file+0x208/0x400 drivers/block/loop.c:667
 RSP <ffff8800a5d5fb70>
---[ end trace 07095bd89e2c5bd5 ]---