FAT-fs (loop4): Can't find a valid FAT filesystem
FAT-fs (loop6): bogus number of reserved sectors
FAT-fs (loop6): Can't find a valid FAT filesystem
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 1 PID: 6710 Comm: syz-executor1 Not tainted 4.18.0-next-20180813+ #37
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:loop_validate_file+0x247/0x470 drivers/block/loop.c:664
Code: 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 2e 02 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 03 02 00 00 4d 8b a4 24 b8 01 00 00 4c 89 e0 48
RSP: 0018:ffff880192fe78f8 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90003e3c000
RDX: 0000000000000054 RSI: ffffffff83dde197 RDI: 00000000000001b8
RBP: ffff880192fe7918 R08: ffff880195e74700 R09: ffffed003b6246d6
R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88018aa1f380 R14: 0000000000000002 R15: ffff88018aa1f380
FS:  00007fa2c1bc4700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32c21000 CR3: 00000001af534000 CR4: 00000000001406e0
DR0: 0000000000000001 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 loop_set_fd drivers/block/loop.c:926 [inline]
 lo_ioctl+0x55c/0x1d70 drivers/block/loop.c:1409
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x9cd/0x2030 block/ioctl.c:601
 block_ioctl+0xee/0x130 fs/block_dev.c:1883
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457089
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa2c1bc3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa2c1bc46d4 RCX: 0000000000457089
RDX: 0000000000000004 RSI: 0000000000004c00 RDI: 0000000000000006
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cf070 R14: 00000000004c58e0 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace 41765e6438a318a1 ]---
RIP: 0010:loop_validate_file+0x247/0x470 drivers/block/loop.c:664
Code: 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 2e 02 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 03 02 00 00 4d 8b a4 24 b8 01 00 00 4c 89 e0 48
RSP: 0018:ffff880192fe78f8 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90003e3c000
RDX: 0000000000000054 RSI: ffffffff83dde197 RDI: 00000000000001b8
RBP: ffff880192fe7918 R08: ffff880195e74700 R09: ffffed003b6246d6
R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88018aa1f380 R14: 0000000000000002 R15: ffff88018aa1f380
FS:  00007fa2c1bc4700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32c21000 CR3: 00000001af534000 CR4: 00000000001406e0
DR0: 0000000000000001 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400