------------[ cut here ]------------
!rwb
WARNING: block/blk-wbt.c:785 at wbt_init_enable_default+0x18a/0x220 block/blk-wbt.c:785, CPU#0: syz.3.5250/31457
Modules linked in:
CPU: 0 UID: 0 PID: 31457 Comm: syz.3.5250 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:wbt_init_enable_default+0x18a/0x220 block/blk-wbt.c:785
Code: 1c 84 c0 0f 85 8d 00 00 00 41 21 2e eb 1f e8 5d 09 26 fd eb 18 e8 56 09 26 fd eb 0d e8 4f 09 26 fd 4c 89 ff e8 c7 fd 83 fd 90 <0f> 0b 90 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc
RSP: 0000:ffffc9000550f8d0 EFLAGS: 00010282
RAX: 85afff06d23ba200 RBX: 1ffff1100f718204 RCX: 0000000000000046
RDX: 0000000000000006 RSI: ffffffff8def122b RDI: ffffffff8c27a500
RBP: dffffc0000000000 R08: ffffffff901170b7 R09: 1ffffffff2022e16
R10: dffffc0000000000 R11: fffffbfff2022e17 R12: ffff88807b8c1020
R13: 0000000000000000 R14: ffff888029f73000 R15: ffff88807b8c1000
FS:  0000000000000000(0000) GS:ffff888125466000(0063) knlGS:00000000f5051b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000030bf9ff8 CR3: 0000000079074000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 blk_register_queue+0x382/0x430 block/blk-sysfs.c:943
 __add_disk+0x677/0xd50 block/genhd.c:528
 add_disk_fwnode+0xfb/0x480 block/genhd.c:597
 add_disk include/linux/blkdev.h:785 [inline]
 loop_add+0x85e/0xb40 drivers/block/loop.c:2093
 loop_control_ioctl+0x12e/0x5a0 drivers/block/loop.c:2220
 __do_compat_sys_ioctl fs/ioctl.c:695 [inline]
 __se_compat_sys_ioctl fs/ioctl.c:638 [inline]
 __ia32_compat_sys_ioctl+0x5ea/0x950 fs/ioctl.c:638
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x20d/0x640 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7ff2f6c
Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 58 b8 77 00 00 00 cd 80 0f 0b 90 90 90 90 90 90 b8 ad
RSP: 002b:00000000f505150c EFLAGS: 00000206 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 000000000000000b RCX: 0000000000004c80
RDX: 00000000ffffffb6 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	85 d2                	test   %edx,%edx
   3:	74 0a                	je     0xf
   5:	89 ce                	mov    %ecx,%esi
   7:	81 e6 ff 0f 00 00    	and    $0xfff,%esi
   d:	89 32                	mov    %esi,(%rdx)
   f:	85 c0                	test   %eax,%eax
  11:	74 05                	je     0x18
  13:	c1 e9 0c             	shr    $0xc,%ecx
  16:	89 08                	mov    %ecx,(%rax)
  18:	31 c0                	xor    %eax,%eax
  1a:	5e                   	pop    %rsi
  1b:	5d                   	pop    %rbp
  1c:	c3                   	ret
  1d:	90                   	nop
  1e:	0f 1f 00             	nopl   (%rax)
  21:	51                   	push   %rcx
  22:	52                   	push   %rdx
  23:	55                   	push   %rbp
  24:	89 e5                	mov    %esp,%ebp
  26:	0f 34                	sysenter
  28:	cd 80                	int    $0x80
* 2a:	5d                   	pop    %rbp <-- trapping instruction
  2b:	5a                   	pop    %rdx
  2c:	59                   	pop    %rcx
  2d:	c3                   	ret
  2e:	58                   	pop    %rax
  2f:	b8 77 00 00 00       	mov    $0x77,%eax
  34:	cd 80                	int    $0x80
  36:	0f 0b                	ud2
  38:	90                   	nop
  39:	90                   	nop
  3a:	90                   	nop
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	b8                   	.byte 0xb8
  3f:	ad                   	lods   %ds:(%rsi),%eax