[syzbot] [block?] WARNING in floppy_interrupt (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3e7bb4f24617 Merge tag '6.3-rc6-smb311-client-negcontext-f..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1304980bc80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c21559e740385326
dashboard link: https://syzkaller.appspot.com/bug?extid=aa45f3927a085bc1b242
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+aa45f3927a085bc1b242@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
WARNING: CPU: 3 PID: 21618 at drivers/block/floppy.c:999 schedule_bh drivers/block/floppy.c:999 [inline]
WARNING: CPU: 3 PID: 21618 at drivers/block/floppy.c:999 floppy_interrupt+0x3cc/0x440 drivers/block/floppy.c:1765
Modules linked in:
CPU: 3 PID: 21618 Comm: kworker/u16:7 Not tainted 6.3.0-rc6-syzkaller-00188-g3e7bb4f24617 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: floppy floppy_work_workfn
RIP: 0010:schedule_bh drivers/block/floppy.c:999 [inline]
RIP: 0010:floppy_interrupt+0x3cc/0x440 drivers/block/floppy.c:1765
Code: 03 cf 8a 89 c6 89 05 63 fa eb 0c e8 7e 27 ff ff 8b 1d 58 fa eb 0c e9 9c fd ff ff e8 8e 5f b7 fc e9 66 fd ff ff e8 24 4d 66 fc <0f> 0b e9 c9 fe ff ff 48 c7 c7 00 f2 40 8c e8 31 5f b7 fc e9 5a fc
RSP: 0018:ffffc900005d8e58 EFLAGS: 00010046
RAX: 0000000080010000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88801d1b1d40 RSI: ffffffff851c9e3c RDI: 0000000000000001
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff851c17e0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000006
FS:  0000000000000000(0000) GS:ffff88802c900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc8f5102dd0 CR3: 000000002655a000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 floppy_hardint+0x1b1/0x200 arch/x86/include/asm/floppy.h:66
 __handle_irq_event_percpu+0x22b/0x730 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
 handle_edge_irq+0x263/0xd00 kernel/irq/chip.c:819
 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
 handle_irq arch/x86/kernel/irq.c:231 [inline]
 __common_interrupt+0xa1/0x220 arch/x86/kernel/irq.c:250
 common_interrupt+0xa8/0xd0 arch/x86/kernel/irq.c:240
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636
RIP: 0010:outb_p arch/x86/include/asm/io.h:296 [inline]
RIP: 0010:fdc_outb drivers/block/floppy.c:602 [inline]
RIP: 0010:reset_fdc+0x185/0x400 drivers/block/floppy.c:1817
Code: ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 11 00 0f 85 8a 01 00 00 48 8d 14 9b 48 8b 14 d5 70 6f 08 92 83 c2 04 ee <e8> 56 ec ff ff 48 83 c4 08 5b 5d e9 ab 05 67 fc e8 a6 05 67 fc 48
RSP: 0018:ffffc9000f2c7c20 EFLAGS: 00000202
RAX: 00000000ffffff83 RBX: 0000000000000000 RCX: 1ffffffff2410dee
RDX: 00000000000003f4 RSI: ffffffff851be51c RDI: ffffffff92086f70
RBP: 0000000000000062 R08: 0000000000000001 R09: 0000000000000044
R10: 0000000000000062 R11: 0000000000000000 R12: ffffffff851ca2e0
R13: 0000000000000001 R14: ffff888049043c00 R15: ffff888012489000
 fd_wait_for_completion+0xd2/0x170 drivers/block/floppy.c:1051
 redo_fd_request+0x1f0/0x3010 drivers/block/floppy.c:2799
 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390
 worker_thread+0x669/0x1090 kernel/workqueue.c:2537
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
----------------
Code disassembly (best guess):
   0:	ba 00 00 00 00       	mov    $0x0,%edx
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	(bad)
   8:	df 48 89             	fisttps -0x77(%rax)
   b:	f9                   	stc
   c:	48 c1 e9 03          	shr    $0x3,%rcx
  10:	80 3c 11 00          	cmpb   $0x0,(%rcx,%rdx,1)
  14:	0f 85 8a 01 00 00    	jne    0x1a4
  1a:	48 8d 14 9b          	lea    (%rbx,%rbx,4),%rdx
  1e:	48 8b 14 d5 70 6f 08 	mov    -0x6df79090(,%rdx,8),%rdx
  25:	92
  26:	83 c2 04             	add    $0x4,%edx
  29:	ee                   	out    %al,(%dx)
* 2a:	e8 56 ec ff ff       	callq  0xffffec85 <-- trapping instruction
  2f:	48 83 c4 08          	add    $0x8,%rsp
  33:	5b                   	pop    %rbx
  34:	5d                   	pop    %rbp
  35:	e9 ab 05 67 fc       	jmpq   0xfc6705e5
  3a:	e8 a6 05 67 fc       	callq  0xfc6705e5
  3f:	48                   	rex.W


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