ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
---[ end trace bc12ee340783dbf4 ]---
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 2351 Comm: syz-executor.4 Tainted: G        W         5.4.225-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
RIP: 0010:kill_device drivers/base/core.c:3022 [inline]
RIP: 0010:device_del+0xe7/0xfa0 drivers/base/core.c:3049
Code: df e8 fd 7e 09 ff 4c 89 7c 24 18 41 bf c8 00 00 00 48 89 5c 24 08 4c 03 3b 4d 89 fc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 0f 85 31 0e 00 00 41 0f b6 1f 89 de 83 e6 01
RSP: 0018:ffff8881e2bd79c0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8881d0df40d8 RCX: 1ffff1103a1be81b
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881e2bd7940
RBP: ffff8881e2bd7a90 R08: dffffc0000000000 R09: ffffed103c57af29
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000019
R13: ffff8881d0df4070 R14: ffff8881d0df4110 R15: 00000000000000c8
FS:  00007f9bcb684700(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc3768bff8 CR3: 00000001e347a000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 del_gendisk+0x99c/0xbf0 block/genhd.c:835
 loop_remove+0x42/0xa0 drivers/block/loop.c:2194
 loop_control_ioctl+0x564/0x620 drivers/block/loop.c:2293
 do_vfs_ioctl+0x742/0x1720 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
Modules linked in:
---[ end trace bc12ee340783dbf5 ]---
RIP: 0010:kill_device drivers/base/core.c:3022 [inline]
RIP: 0010:device_del+0xe7/0xfa0 drivers/base/core.c:3049
Code: df e8 fd 7e 09 ff 4c 89 7c 24 18 41 bf c8 00 00 00 48 89 5c 24 08 4c 03 3b 4d 89 fc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 0f 85 31 0e 00 00 41 0f b6 1f 89 de 83 e6 01
RSP: 0018:ffff8881e2bd79c0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8881d0df40d8 RCX: 1ffff1103a1be81b
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881e2bd7940
RBP: ffff8881e2bd7a90 R08: dffffc0000000000 R09: ffffed103c57af29
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000019
R13: ffff8881d0df4070 R14: ffff8881d0df4110 R15: 00000000000000c8
FS:  00007f9bcb684700(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc3768bff8 CR3: 00000001e347a000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	df e8                	fucomip %st(0),%st
   2:	fd                   	std
   3:	7e 09                	jle    0xe
   5:	ff 4c 89 7c          	decl   0x7c(%rcx,%rcx,4)
   9:	24 18                	and    $0x18,%al
   b:	41 bf c8 00 00 00    	mov    $0xc8,%r15d
  11:	48 89 5c 24 08       	mov    %rbx,0x8(%rsp)
  16:	4c 03 3b             	add    (%rbx),%r15
  19:	4d 89 fc             	mov    %r15,%r12
  1c:	49 c1 ec 03          	shr    $0x3,%r12
  20:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  27:	fc ff df
* 2a:	41 0f b6 04 04       	movzbl (%r12,%rax,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 31 0e 00 00    	jne    0xe68
  37:	41 0f b6 1f          	movzbl (%r15),%ebx
  3b:	89 de                	mov    %ebx,%esi
  3d:	83 e6 01             	and    $0x1,%esi