Bug 437115

Summary: kwin_wayland crashes when firefox-nightly starts if gfx.webrender.compositor.force-enabled=true
Product: [Plasma] kwin Reporter: Henrique Sant'Anna <hsantanna>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: crash    
Priority: NOR    
Version: 5.21.5   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
See Also: https://bugs.kde.org/show_bug.cgi?id=434631
Latest Commit: https://invent.kde.org/plasma/kwayland-server/-/commit/512464af3d5d69ce8988fe1a53fbc3cda4ceaa06 Version Fixed In: 5.22.0
Sentry Crash Report:

Description Henrique Sant'Anna 2021-05-14 19:41:23 UTC 
SUMMARY

I updated firefox-nightly on Arch Linux to 90.0a1 (2021-05-13) and I'm getting compositor crash on KDE Plasma Wayland (kwin_wayland) every time firefox-nightly is started.

Tested with firefox-nightly --safe-mode and that way kwin_wayland compositor will not crash.

So I figured out that it was related to Firefox's gfx.webrender.compositor.force-enabled=true about:config setting.

Opening firefox-nightly on XWayland (works) and setting gfx.webrender.compositor.force-enabled=false solved the compositor crashing, so I can start the current nightly version as an Wayland client again.


STEPS TO REPRODUCE

0. Start KDE Plasma (Wayland)
1. Install and open firefox-nightly 90.0a1 (2021-05-13)
2. go to about:config and set:
- gfx.webrender.compositor = true
- gfx.webrender.compositor.force-enabled = true
3. Quit Firefox Nighly (Ctrl+Q)
4. Start Firefox Nightly with `MOZ_ENABLE_WAYLAND=1 firefox-nightly`
5. kwin_wayland will crash and all open apps will die.


OBSERVED RESULT

kwin_wayland compositor will crash when firefox-nightly is started.

My previous firefox-nightly version (90.0a1 (2021-05-07)) was working good even with gfx.webrender.compositor.force-enabled=true.


EXPECTED RESULT

kwin_wayland should not crash when firefox-nightly starts and all open apps should not die together. 


SOFTWARE/OS VERSIONS

Linux: 5.12.3-arch1 (Arch Linux)
KDE Plasma Version: 5.21.5
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2+kde+r192-1


ADDITIONAL INFORMATION

Please, I would appreciate any info on how to debug this.
Comment 1 Vlad Zahorodnii 2021-05-14 19:42:27 UTC 
It's fixed in git master and also 5.22.0
Comment 2 Henrique Sant'Anna 2021-05-17 18:41:54 UTC 
Here is the bug report on Firefox's side:
https://bugzilla.mozilla.org/show_bug.cgi?id=1711266

There we figured out that the crash is probably related to kwin_wayland wp_viewporter (un)support protocol, already requested by Bug 434631.
Comment 3 Henrique Sant'Anna 2021-05-18 17:50:03 UTC 
Tested and I can confirm that it is fixed on git master.