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From: Oliver Neukum <oneukum@suse.com>
To: Alan Stern <stern@rowland.harvard.edu>, Oliver Neukum <oneukum@suse.com>
Cc: syzbot <syzbot+28748250ab47a8f04100@syzkaller.appspotmail.com>,
	bvanassche@acm.org, emilne@redhat.com,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	linux-usb@vger.kernel.org, martin.petersen@oracle.com,
	syzkaller-bugs@googlegroups.com, tasos@tasossah.com,
	usb-storage@lists.one-eyed-alien.net
Subject: Re: [syzbot] [usb-storage?] divide error in isd200_ata_command
Date: Wed, 28 Feb 2024 17:20:29 +0100	[thread overview]
Message-ID: <12b30393-0b4b-400e-828b-231901d8933b@suse.com> (raw)
In-Reply-To: <9bbc5b63-33e3-44de-8bce-4c59dcce5e92@rowland.harvard.edu>

On 26.02.24 19:13, Alan Stern wrote:

>> It oopses here:
>>
>> 		} else {
>> 			if (!id[ATA_ID_SECTORS] || !id[ATA_ID_HEADS])
>> 				goto too_early;
> 
> Those two lines are debugging code you added, right?

Yes, sorry about that.

> 
>> 			sectnum = (u8)((lba % id[ATA_ID_SECTORS]) + 1);
>> 			cylinder = (u16)(lba / (id[ATA_ID_SECTORS] *
>> 					id[ATA_ID_HEADS]));
>>
>> in isd200_scsi_to_ata() because it must not be called before isd200_get_inquiry_data()
>> has completed.
> 
> It can't be; isd200_get_inquiry_data is called by isd200_Initialization
> during probe before any SCSI commands are transmitted.

So, you are concluding that the bisection is spurious because
without that patch the SCSI layer would see a capacity of zero
and not even try to read anything?

	Regards
		Oliver


  parent reply	other threads:[~2024-02-28 16:20 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-26  9:42 [syzbot] [usb-storage?] divide error in isd200_ata_command syzbot
2024-02-26 10:59 ` Oliver Neukum
2024-02-26 18:13   ` Alan Stern
2024-02-27  2:46     ` Martin K. Petersen
2024-02-27  3:05       ` Alan Stern
2024-02-28 16:20     ` Oliver Neukum [this message]
2024-02-28 19:23       ` Alan Stern
2024-02-27 19:36 ` Alan Stern
2024-02-28  5:20   ` syzbot
2024-02-28 16:12     ` Alan Stern
2024-02-28 16:13       ` syzbot
2024-02-28 16:52       ` Aleksandr Nogikh
2024-02-28 19:18         ` Alan Stern
2024-02-29  0:33           ` syzbot
2024-02-29 19:30             ` [PATCH] USB: usb-storage: Prevent divide-by-0 " Alan Stern
2024-03-01  1:11               ` Martin K. Petersen
2024-03-01 11:36               ` PrasannaKumar Muralidharan
2024-02-29 15:40           ` [syzbot] [usb-storage?] divide " Aleksandr Nogikh
2024-02-29 16:12             ` Alan Stern
2024-02-29 17:57               ` Aleksandr Nogikh

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