Re: [PATCH] USB: UAS: don't unbind and rebind the driver during usb_reset_device

[Hui Wang <hui.wang@canonical.com>]

On 2/22/21 9:50 PM, Oliver Neukum wrote:
> Am Montag, den 22.02.2021, 21:02 +0800 schrieb Hui Wang:
>> On 2/22/21 8:51 PM, Oliver Neukum wrote:
>>> Am Montag, den 22.02.2021, 20:40 +0800 schrieb Hui Wang:
>>>> On 2/22/21 3:59 PM, Oliver Neukum wrote:
>>>> OK, will find a UAS device to do the test.
>>> Hi,
>>>
>>> do you have a design at all?
>> No, so far what I could find is all driven by usb-storage, I tested a
>> couple of usb-sdcard-readers and usb-scsi/ata disk adapters, they all
>> belong to USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI,
>> USB_PR_BULK) instead of USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE,
>> USB_SC_SCSI, USB_PR_UAS). I plan to go to the office to find some usb
>> storage devices to test.
> Hi,
>
> please wait.  First of all, you are making the assumption that all
> resets originate from the SCSI layer. You cannot make that assumption.
>
> Secondly, yes, ideally we should not pretend that a disconnect has
> happened, when it hasn't happened, but what is your alternative.
> What exactly do you want to test? You have not even defined the
> desirable behavior and the problem you are seeing with the current
> behavior.

I planed to forcibly (simulate) trigger calling 
eh_device_reset_handler() from scsi layer and let pre_reset() or 
post_reset() return a non-zero, and test if there is use-after-free 
issue in the rest part of eh_device_reset_handler() and its callers. But 
after thinking of your comment, looks like I was wrong. Thanks for your 
instructions on this issue.

Thanks,

Hui.

> 	Regards
> 		Oliver
>
>