Bug 512557

Created attachment 187122 [details]
eglinfo output

SUMMARY
After a recent system update (from Fedora 41 to Fedora 43) kmail crashes when navigating from message to message in the message list.

STEPS TO REPRODUCE
1. start kmail
2. click on some message titles in the message list

OBSERVED RESULT
Crash after two or three clicks

The console shows this output:
$ kmail
org.kde.pim.pimcommonactivities: Plasma activities is not running:  1
GBM is not supported with the current configuration. Fallback to Vulkan rendering in Chromium.
org.kde.pim.mailtransport: We have an error during reading password for 1396373894 "Entry not found"
[4203:4285:1124/120125.533324:ERROR:shared_context_state.cc(1345)] SharedContextState context lost via Skia OOM.
[4203:4285:1124/120125.533457:ERROR:shared_image_factory.cc(916)] CreateSharedImage: could not create backing.
[4203:4285:1124/120125.533468:ERROR:native_skia_output_device.cpp(278)] CreateSharedImage failed.
[4203:4285:1124/120125.741143:ERROR:shared_context_state.cc(1007)] Failed to make current since context is marked as lost
[4203:4285:1124/120125.743026:ERROR:shared_context_state.cc(1007)] Failed to make current since context is marked as lost
[4203:4285:1124/120125.743044:ERROR:skia_output_surface_impl_on_gpu.cc(2270)] Failed to make current.
NativeSkiaOutputDevice: Leaking graphics resources.
[4203:4285:1124/120125.743094:ERROR:shared_context_state.cc(1007)] Failed to make current since context is marked as lost
*** KMail got signal 11 (Exiting)
*** Dead letters dumped.
/tmp/messageviewer_KCMaIe.index.2 was not removed .
/tmp/messageviewer_KCMaIe.index.2 was removed .
KCrash: Application 'kmail' crashing... crashRecursionCounter = 2
Segmentatiefout            (geheugendump gemaakt) kmail


EXPECTED RESULT
Kmail functioning normally

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 43
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.1
Kernel Version: 6.17.8-300.fc43.x86_64 (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-6700K CPU @ 4.00GHz
Memory: 48 GiB of RAM (47.0 GiB usable)
Graphics Processor: NVIDIA GeForce GT 1030

ADDITIONAL INFORMATION
The crucial bit seems to be 
"GBM is not supported with the current configuration. Fallback to Vulkan rendering in Chromium."

I searched the internet for suggestions and I found I can work around this bug if I start kmail as follows:
$ QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu" kmail

In that case the GBM/Vulkan fallback message is not shown and kmail is fully functional.

Bug 501858 is also about issues with Vulkan, albeit on plasmashell rather than kmail2. That bug suggests the main issue is that plasma/kmail fall back to software rendering on my system for some reason. Vulkan is the fallback renderer, but that one doesn't seem stable.

So the main question to answer here is, why is my system falling back to software rendering in the first place ? The complaint about GBM above seems to be a hint, but I don't know enough about how the graphics stack solve this myself.

As bug 501858 also asked the OP for the output of eglinfo, I have attached mine to this bug. Note that while generating this output, eglinfo already printed warnings on my console:
$ eglinfo > eglinfo.txt
libEGL warning: pci id for fd 24: 10de:1d01, driver (null)

pci id for fd 34: 10de:1d01, driver (null)
pci id for fd 35: 10de:1d01, driver (null)
libEGL warning: egl: failed to create dri2 screen
libEGL warning: pci id for fd 24: 10de:1d01, driver (null)

pci id for fd 34: 10de:1d01, driver (null)
pci id for fd 35: 10de:1d01, driver (null)
libEGL warning: egl: failed to create dri2 screen
libEGL warning: pci id for fd 24: 10de:1d01, driver (null)

I don't know if they are relevant.