Re: [Gimp-print-devel] [Patch] gutenprint53+usb crashes with libusb-1.0.25

[Zdenek D. <zd...@re...>]

Hi Solomon,

I hope you are well! :)

Did you have a time to get into the issue?

If you didn't, would it be okay for you if I applied the attached patch 
in Fedora for now?


Have a nice Friday!


Zdenek

On 2/24/22 06:25, Zdenek Dohnal wrote:
>
> On 2/23/22 10:25, Benjamin Berg wrote:
>> Hi,
>>
>> On Wed, 2022-02-23 at 09:34 +0100, Zdenek Dohnal wrote:
>>> thank you for looking into the issue!
>>>
>>> On 2/22/22 19:00, Solomon Peachy wrote:
>>>> On Tue, Feb 22, 2022 at 07:55:18AM +0100, Zdenek Dohnal wrote:
>>>>> there were changes in libusb 1.0.25 which is in Fedora 36 - f.e. 
>>>>> default USB
>>>>> context is not initialized unless you specifically pass NULL into
>>>>> `libusb_init()` - gutenprint53+usb backend actually depended on 
>>>>> this hidden
>>>>> behavior, because it passes its own context address into 
>>>>> `libusb_init()`
>>>>> instead of NULL. So the change causes the backend to crash if you 
>>>>> run it:
>>>> Yikes!
>>>>
>>>>> According libusb maintainer, Ben Berg, the backend can work with 
>>>>> the default
>>>>> USB context and he prepared the patch for it (the file is 
>>>>> attached). I was
>>>>> able to verify the patch fixes the crash, but I don't have a device
>>>>> supported by gutenprint itself, so I couldn't do an additional sanity
>>>>> testing. The patch looks good to me though.
>>>> Will this work for multi-threaded stuff where there could 
>>>> conceivably be
>>>> multiple contexts in use?  That's not being exercised in the current
>>>> gutenprint code but some of the stuff I have cooking will change that.
>>> Ben, would you mind looking into it? IMO we probably cannot use a
>>> default USB context for multi-threading...
>>>
>>> In such case, IMO we can init the default context just for the
>>> print_help() scope and close it after we're done with it.
>>>
>>> You can join us in discussion on the bug if you are able as well [1],
>>> I've pinged Robert there as well, because I didn't know your email for
>>> bugzilla...
>> I am already subscribed to that bug. :)
> I'm sorry for mystification... (that's what I got for adding text into 
> email at last minute and don't read it as whole at the end) - I meant 
> Solomon in the last paragraph :)
>>
-- 
Zdenek Dohnal
Software Engineer
Red Hat, BRQ-TPBC