[syzbot] WARNING in floppy_interrupt

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    4a57a8400075 vf/remap: return the amount of bytes actually..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=119ac0fc080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cd73026ceaed1402
dashboard link: https://syzkaller.appspot.com/bug?extid=7c9e87a5d6b088cd78a3
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7c9e87a5d6b088cd78a3@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
WARNING: CPU: 3 PID: 33 at drivers/block/floppy.c:999 schedule_bh drivers/block/floppy.c:999 [inline]
WARNING: CPU: 3 PID: 33 at drivers/block/floppy.c:999 floppy_interrupt+0x32b/0x3a0 drivers/block/floppy.c:1765
Modules linked in:
CPU: 3 PID: 33 Comm: ksoftirqd/3 Not tainted 5.19.0-rc6-syzkaller-00115-g4a57a8400075 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:schedule_bh drivers/block/floppy.c:999 [inline]
RIP: 0010:floppy_interrupt+0x32b/0x3a0 drivers/block/floppy.c:1765
Code: fe ff ff e8 87 25 e0 fc 0f b6 1d 80 24 89 0c 31 ff 89 de e8 77 21 e0 fc 84 db 0f 85 30 b6 ad 04 e9 18 fe ff ff e8 65 25 e0 fc <0f> 0b e9 1a ff ff ff e8 29 e1 2c fd e9 ed fd ff ff e8 1f e1 2c fd
RSP: 0018:ffffc900005d8e58 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000100
RDX: ffff888012229d80 RSI: ffffffff849a457b RDI: 0000000000000007
RBP: 0000000000000001 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000002
R13: ffffffff8499f800 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f6f5c034 CR3: 000000000ba8e000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 floppy_hardint+0x1ad/0x200 arch/x86/include/asm/floppy.h:66
 __handle_irq_event_percpu+0x22b/0x880 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0xa7/0x1e0 kernel/irq/handle.c:210
 handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:817
 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
 handle_irq arch/x86/kernel/irq.c:231 [inline]
 __common_interrupt+0x9d/0x210 arch/x86/kernel/irq.c:250
 common_interrupt+0xa4/0xc0 arch/x86/kernel/irq.c:240
 </IRQ>
 <TASK>
 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:640
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194
Code: 74 24 10 e8 ca de e3 f7 48 89 ef e8 d2 5f e4 f7 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 <e8> 43 67 d7 f7 65 8b 05 fc fb 87 76 85 c0 74 0a 5b 5d c3 e8 90 46
RSP: 0018:ffffc900005afbe0 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff1b77019
RDX: 0000000000000000 RSI: 0000000000000101 RDI: 0000000000000001
RBP: ffffffff91193240 R08: 0000000000000001 R09: 0000000000000001
R10: fffffbfff2232648 R11: 0000000000000001 R12: 0000000000000002
R13: 0000000000000002 R14: dead000000000100 R15: dffffc0000000000
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x20c/0x420 lib/debugobjects.c:1020
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0xeb/0x1c0 mm/slub.c:1780
 slab_free mm/slub.c:3536 [inline]
 kmem_cache_free+0xdd/0x5a0 mm/slub.c:3553
 i_callback+0x3f/0x70 fs/inode.c:249
 rcu_do_batch kernel/rcu/tree.c:2578 [inline]
 rcu_core+0x7b1/0x1880 kernel/rcu/tree.c:2838
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:571
 run_ksoftirqd kernel/softirq.c:934 [inline]
 run_ksoftirqd+0x2d/0x60 kernel/softirq.c:926
 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
----------------
Code disassembly (best guess):
   0:	74 24                	je     0x26
   2:	10 e8                	adc    %ch,%al
   4:	ca de e3             	lret   $0xe3de
   7:	f7 48 89 ef e8 d2 5f 	testl  $0x5fd2e8ef,-0x77(%rax)
   e:	e4 f7                	in     $0xf7,%al
  10:	81 e3 00 02 00 00    	and    $0x200,%ebx
  16:	75 25                	jne    0x3d
  18:	9c                   	pushfq
  19:	58                   	pop    %rax
  1a:	f6 c4 02             	test   $0x2,%ah
  1d:	75 2d                	jne    0x4c
  1f:	48 85 db             	test   %rbx,%rbx
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 43 67 d7 f7       	callq  0xf7d76772 <-- trapping instruction
  2f:	65 8b 05 fc fb 87 76 	mov    %gs:0x7687fbfc(%rip),%eax        # 0x7687fc32
  36:	85 c0                	test   %eax,%eax
  38:	74 0a                	je     0x44
  3a:	5b                   	pop    %rbx
  3b:	5d                   	pop    %rbp
  3c:	c3                   	retq
  3d:	e8                   	.byte 0xe8
  3e:	90                   	nop
  3f:	46                   	rex.RX


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