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Date:   Mon, 3 Apr 2023 10:54:05 +0200
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Subject: Re: [syzbot] WARNING in sisusb_send_bulk_msg/usb_submit_urb
To:     Alan Stern <stern@rowland.harvard.edu>,
        syzbot <syzbot+23be03b56c5259385d79@syzkaller.appspotmail.com>,
        Thomas Winischhofer <thomas@winischhofer.net>
Cc:     linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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 <b799fc68-8840-43e7-85f5-27e1e6457a44@rowland.harvard.edu>
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From:   Oliver Neukum <oneukum@suse.com>
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On 30.03.23 17:34, Alan Stern wrote:
> Reference: https://syzkaller.appspot.com/bug?extid=23be03b56c5259385d79
> 
> The sisusbvga driver just assumes that the endpoints it uses will be
> present, without checking.  I don't know anything about this driver, so
> the fix below may not be entirely correct.

Hi,

this patch by itself looks good to me.

But the need for it is problematic. Do we have any vendor specific driver
that could get away without an equivalent to this patch without showing
an equivalent bug? If so, why do we have a generic matching code, although
it is always insufficient?

What is the purpose of a generic binding interface in sysfs if every probe()
method blocks it? Allowing a generic probe looks like a misdesign under these
circumstances. You'd really want to add IDs to drivers.

	Regards
		Oliver