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: 18833 Comm: syz-executor4 Not tainted 4.4.153+ #29
task: ffff8801d21c0000 task.stack: ffff8801c2260000
RIP: 0010:[<ffffffff81cd8108>]  [<ffffffff81cd8108>] is_loop_device drivers/block/loop.c:656 [inline]
RIP: 0010:[<ffffffff81cd8108>]  [<ffffffff81cd8108>] loop_validate_file+0x208/0x400 drivers/block/loop.c:667
RSP: 0018:ffff8801c2267ad0  EFLAGS: 00010206
blk_update_request: I/O error, dev loop0, sector 0
Buffer I/O error on dev loop0, logical block 0, lost async page write
blk_update_request: I/O error, dev loop0, sector 8
Buffer I/O error on dev loop0, logical block 1, lost async page write
blk_update_request: I/O error, dev loop0, sector 16
Buffer I/O error on dev loop0, logical block 2, lost async page write
blk_update_request: I/O error, dev loop0, sector 24
Buffer I/O error on dev loop0, logical block 3, lost async page write
blk_update_request: I/O error, dev loop0, sector 32
Buffer I/O error on dev loop0, logical block 4, lost async page write
blk_update_request: I/O error, dev loop0, sector 40
Buffer I/O error on dev loop0, logical block 5, lost async page write
blk_update_request: I/O error, dev loop0, sector 48
Buffer I/O error on dev loop0, logical block 6, lost async page write
blk_update_request: I/O error, dev loop0, sector 56
Buffer I/O error on dev loop0, logical block 7, lost async page write
blk_update_request: I/O error, dev loop0, sector 64
Buffer I/O error on dev loop0, logical block 8, lost async page write
blk_update_request: I/O error, dev loop0, sector 72
RAX: 0000000000000036 RBX: dffffc0000000000 RCX: ffffc90003682000
RDX: 000000000000008d RSI: ffffffff81cd80d8 RDI: 00000000000001b0
RBP: ffff8801c2267ae8 R08: ffff8801d21c08c8 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff8801d59aa280 R14: ffff8801d59aa280 R15: ffff8801d83fdc58
FS:  0000000000000000(0000) GS:ffff8801db600000(0063) knlGS:00000000f5704b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00007f775dded4a0 CR3: 00000001d571a000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d83fdb00 ffff8800b677c000 0000000000000003 ffff8801c2267b78
 ffffffff81ce162d ffff8800b9f26748 ffff880100000001 ffff8801d83fdb10
 ffff8801d83fdd38 ffff8801d83fdb18 ffff880100001000 4788fd1ab188071a
Call Trace:
 [<ffffffff81ce162d>] loop_change_fd drivers/block/loop.c:713 [inline]
 [<ffffffff81ce162d>] lo_ioctl+0x3ed/0x16b0 drivers/block/loop.c:1370
 [<ffffffff81ce29a2>] lo_compat_ioctl+0xb2/0x140 drivers/block/loop.c:1560
 [<ffffffff81a4df94>] compat_blkdev_ioctl+0x3a4/0x37eb block/compat_ioctl.c:751
 [<ffffffff8156d44e>] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline]
 [<ffffffff8156d44e>] compat_SyS_ioctl+0x62e/0x22a0 fs/compat_ioctl.c:1544
 [<ffffffff81005ffe>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81005ffe>] do_fast_syscall_32+0x31e/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff82691490>] sysenter_flags_fixed+0xd/0x1a
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  [<ffffffff81cd8108>] is_loop_device drivers/block/loop.c:656 [inline]
RIP  [<ffffffff81cd8108>] loop_validate_file+0x208/0x400 drivers/block/loop.c:667
 RSP <ffff8801c2267ad0>
---[ end trace 95a53d8dae68507a ]---