RBP: 00007f948c00c08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff870ca2cf R14: 00007f948b128300 R15: 0000000000022000
---[ end trace e58ba63927ee04ed ]---
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 21720 Comm: syz-executor.4 Tainted: G        W         5.10.109-syzkaller-00693-g414e6c8e941c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:strlen+0x3a/0x80 lib/string.c:568
Code: c0 ff ff ff ff 49 bf 00 00 00 00 00 fc ff df 48 89 fb 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 49 89 c4 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 75 12 48 ff c3 49 8d 44 24 01 43 80 7c 26 01
RSP: 0018:ffffc90009a8fb68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc90002113000 RSI: 000000000003ffff RDI: 0000000000000000
RBP: ffffc90009a8fb88 R08: ffffffff81d12c3c R09: fffff52001351f75
R10: fffff52001351f75 R11: 1ffff92001351f74 R12: ffffffffffffffff
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f948b128700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33321000 CR3: 000000010b93b000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kernfs_name_hash+0x21/0x240 fs/kernfs/dir.c:302
 kernfs_find_ns+0x72/0x280 fs/kernfs/dir.c:841
 kernfs_remove_by_name_ns+0x36/0x90 fs/kernfs/dir.c:1514
 kernfs_remove_by_name include/linux/kernfs.h:608 [inline]
 sysfs_remove_link+0x50/0x60 fs/sysfs/symlink.c:152
 del_gendisk+0xbe0/0xe20 block/genhd.c:951
 loop_remove+0x46/0xb0 drivers/block/loop.c:2185
 loop_control_ioctl+0x67f/0x740 drivers/block/loop.c:2284
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f948bfb20e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f948b128168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f948c0c4f60 RCX: 00007f948bfb20e9
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000005
RBP: 00007f948c00c08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff870ca2cf R14: 00007f948b128300 R15: 0000000000022000
Modules linked in:
---[ end trace e58ba63927ee04ee ]---
RIP: 0010:strlen+0x3a/0x80 lib/string.c:568
Code: c0 ff ff ff ff 49 bf 00 00 00 00 00 fc ff df 48 89 fb 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 49 89 c4 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 75 12 48 ff c3 49 8d 44 24 01 43 80 7c 26 01
RSP: 0018:ffffc90009a8fb68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc90002113000 RSI: 000000000003ffff RDI: 0000000000000000
RBP: ffffc90009a8fb88 R08: ffffffff81d12c3c R09: fffff52001351f75
R10: fffff52001351f75 R11: 1ffff92001351f74 R12: ffffffffffffffff
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f948b128700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33321000 CR3: 000000010b93b000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 5 bytes skipped:
   0:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
   7:	fc ff df
   a:	48 89 fb             	mov    %rdi,%rbx
   d:	66 66 2e 0f 1f 84 00 	data16 nopw %cs:0x0(%rax,%rax,1)
  14:	00 00 00 00
  18:	0f 1f 00             	nopl   (%rax)
  1b:	49 89 c4             	mov    %rax,%r12
  1e:	48 89 d8             	mov    %rbx,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
* 25:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2a:	84 c0                	test   %al,%al
  2c:	75 12                	jne    0x40
  2e:	48 ff c3             	inc    %rbx
  31:	49 8d 44 24 01       	lea    0x1(%r12),%rax
  36:	43                   	rex.XB
  37:	80                   	.byte 0x80
  38:	7c 26                	jl     0x60
  3a:	01                   	.byte 0x1