floppy1: FDC access conflict!
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 12 Comm: kworker/u16:1 Not tainted 6.0.0-rc2-syzkaller-00283-g10d4879f9ef0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Workqueue: floppy floppy_work_workfn
RIP: 0010:start_motor+0x3a/0x3f0 drivers/block/floppy.c:1905
Code: 08 e8 7a 39 e0 fc 48 8b 1d 63 54 ae 0c 48 b8 00 00 00 00 00 fc ff df 0f b6 2d b2 3e ae 0c 48 89 da 48 c1 ea 03 89 e9 41 89 ed <0f> b6 04 02 83 e1 03 41 83 e5 03 84 c0 74 08 3c 03 0f 8e be 02 00
RSP: 0018:ffffc900005ffc98 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff849b0096 RDI: ffffffff849b2f00
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff849b2f00
R13: 0000000000000001 R14: ffff888012459400 R15: ffff888011875800
FS: 0000000000000000(0000) GS:ffff88802c900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0afb5ff718 CR3: 000000001b6a0000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
floppy_ready+0x83/0x1940 drivers/block/floppy.c:1932
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:start_motor+0x3a/0x3f0 drivers/block/floppy.c:1905
Code: 08 e8 7a 39 e0 fc 48 8b 1d 63 54 ae 0c 48 b8 00 00 00 00 00 fc ff df 0f b6 2d b2 3e ae 0c 48 89 da 48 c1 ea 03 89 e9 41 89 ed <0f> b6 04 02 83 e1 03 41 83 e5 03 84 c0 74 08 3c 03 0f 8e be 02 00
RSP: 0018:ffffc900005ffc98 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff849b0096 RDI: ffffffff849b2f00
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff849b2f00
R13: 0000000000000001 R14: ffff888012459400 R15: ffff888011875800
FS: 0000000000000000(0000) GS:ffff88802c900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0afb5ff718 CR3: 00000000284ad000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 08 e8 or %ch,%al
2: 7a 39 jp 0x3d
4: e0 fc loopne 0x2
6: 48 8b 1d 63 54 ae 0c mov 0xcae5463(%rip),%rbx # 0xcae5470
d: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
14: fc ff df
17: 0f b6 2d b2 3e ae 0c movzbl 0xcae3eb2(%rip),%ebp # 0xcae3ed0
1e: 48 89 da mov %rbx,%rdx
21: 48 c1 ea 03 shr $0x3,%rdx
25: 89 e9 mov %ebp,%ecx
27: 41 89 ed mov %ebp,%r13d
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 83 e1 03 and $0x3,%ecx
31: 41 83 e5 03 and $0x3,%r13d
35: 84 c0 test %al,%al
37: 74 08 je 0x41
39: 3c 03 cmp $0x3,%al
3b: 0f .byte 0xf
3c: 8e .byte 0x8e
3d: be .byte 0xbe
3e: 02 00 add (%rax),%al