[syzbot] general protection fault in reset_interrupt (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    50fd82b3a9a9 Merge tag 'docs-5.19-2' of git://git.lwn.net/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b08fbdf00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bb7e6d86633f6f71
dashboard link: https://syzkaller.appspot.com/bug?extid=682e25dfa0255204491a
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=165f5277f00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=171403aff00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+682e25dfa0255204491a@xxxxxxxxxxxxxxxxxxxxxxxxx

c1 00                                            ..
status=d0
fdc_busy=0
cont=0000000000000000
current_req=0000000000000000
command_status=-1
general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 3 PID: 3441 Comm: kworker/u16:2 Not tainted 5.18.0-syzkaller-12234-g50fd82b3a9a9 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: floppy floppy_work_workfn
RIP: 0010:reset_interrupt.cold+0x3d/0x88 drivers/block/floppy.c:1789
Code: e8 da f0 ff ff e9 89 61 52 fb e8 e1 39 33 f8 48 8b 1d 8a 3b dd 07 b8 ff ff 37 00 48 c1 e0 2a 48 8d 7b 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 3e 48 8b 73 10 48 c7 c7 40 51 42 8a e8 5c 28 eb ff
RSP: 0018:ffffc90002d2fd08 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff89467b8f RDI: 0000000000000010
RBP: ffffffff8c8e71e0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: ffffc90002d2fda8 R14: ffff888014ba4100 R15: ffff888011875800
FS:  0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f751b73001d CR3: 000000001f1bf000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 process_one_work+0x996/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:reset_interrupt.cold+0x3d/0x88 drivers/block/floppy.c:1789
Code: e8 da f0 ff ff e9 89 61 52 fb e8 e1 39 33 f8 48 8b 1d 8a 3b dd 07 b8 ff ff 37 00 48 c1 e0 2a 48 8d 7b 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 3e 48 8b 73 10 48 c7 c7 40 51 42 8a e8 5c 28 eb ff
RSP: 0018:ffffc90002d2fd08 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff89467b8f RDI: 0000000000000010
RBP: ffffffff8c8e71e0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: ffffc90002d2fda8 R14: ffff888014ba4100 R15: ffff888011875800
FS:  0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f751b73001d CR3: 000000001f1bf000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	e8 da f0 ff ff       	callq  0xfffff0df
   5:	e9 89 61 52 fb       	jmpq   0xfb526193
   a:	e8 e1 39 33 f8       	callq  0xf83339f0
   f:	48 8b 1d 8a 3b dd 07 	mov    0x7dd3b8a(%rip),%rbx        # 0x7dd3ba0
  16:	b8 ff ff 37 00       	mov    $0x37ffff,%eax
  1b:	48 c1 e0 2a          	shl    $0x2a,%rax
  1f:	48 8d 7b 10          	lea    0x10(%rbx),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	75 3e                	jne    0x6e
  30:	48 8b 73 10          	mov    0x10(%rbx),%rsi
  34:	48 c7 c7 40 51 42 8a 	mov    $0xffffffff8a425140,%rdi
  3b:	e8 5c 28 eb ff       	callq  0xffeb289c


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