evince crashes the X server

[Vladimir Dergachev]

On Thu, 10 Jul 2025, Dave Howorth wrote:

> On Thu, 10 Jul 2025 09:33:12 -0400 (EDT), Vladimir Dergachev wrote:
>>
>> Interesting!
>>
>> This suggests your intel driver is rather new and has this bug, as on
>> my systems (Kubuntu LTS) intel_drv.so does not have references to
>> imprecise_trapezoid_span_converter. In fact it is so bleeding edge
>> that Google does not show hits to repository with
>> "imprecise_trapezoid_span_converter".
>>
>> Looks like intel driver contains two bugs: whatever triggers the
>> assertion, and assertion that when violated exits X-server. It is
>> likely a drawing code, so it could just draw nothing.
>>
>> I would suggest first to check RedHat changelogs to see where the
>> code came from and whether they backported any patches. It could be
>> the error occurred during porting. If this is not the case, then
>> contact intel_drv developers, which I think is Intel - they should
>> have forums to post a question to.
>>
>> best
>>
>> Vladimir Dergachev
>
> See
> https://gitlab.freedesktop.org/xorg/driver/xf86-video-intel/-/blob/master/src/sna/sna_trapezoids_imprecise.c
>
> for a/the definition of the function. It hasn't been changed in ten
> years though, so something else must be causing a problem, I think.
>

Thanks!

You are quite right - the assertion is right there on line 2021. The code 
uses multiple threads just before it, so it might be guarding against 
memory corruption, which would justify the exit.

I am really very surprised that Google does not find this code.

To Eyal - it might make sense to file a bug with Fedora/Redhat first, and 
to get things working rollback to an earlier driver.

best

Vladimir Dergachev