Public bug reported:
## Summary
gnome-shell crashes with SIGSEGV when Microsoft Edge initiates screen capture
via PipeWire/xdg-desktop-portal. The crash is preceded by repeated
"cogl_framebuffer_blit premult mismatch" and EGLImage destruction errors.
## System Information
- Ubuntu Version: 25.10 (Questing)
- Kernel: 6.19.0-061900rc5-generic
- GPU: Intel Corporation Meteor Lake-P [Intel Arc Graphics] (rev 08)
- GNOME Shell: 49.0-1ubuntu1.2
- Mutter: 49.0-2ubuntu5.3
- Mesa: 25.2.3-1ubuntu1
- Display Server: Wayland
## Steps to Reproduce
1. Run GNOME Shell on Wayland with Intel Meteor Lake GPU
2. Open Microsoft Edge (or other Chromium-based browser)
3. Initiate screen sharing/capture (e.g., video call, WebRTC screen share)
4. gnome-shell crashes, logging out the session
## What I Expected
Screen sharing should work without crashing the desktop session.
## What Happened Instead
gnome-shell crashed with SIGSEGV, terminating the entire session and losing all
open windows.
## Crash Details
- Signal: 11 (SIGSEGV)
- Crash file available: /var/crash/_usr_bin_gnome-shell.1000.crash (76MB)
## Journal Logs (chronological)
```
Jan 16 09:03:35 xdg-desktop-portal-gnome: MESA-INTEL: warning:
../src/intel/vulkan/anv_formats.c:949: FINISHME: support YUV colorspace with
DRM format modifiers
Jan 16 09:03:46 microsoft-edge.desktop: [ERROR:screencast_portal.cc:369] Failed
to start the screen cast session.
Jan 16 09:03:46 microsoft-edge.desktop: [ERROR:base_capturer_pipewire.cc:93]
ScreenCastPortal failed: 2
Jan 16 09:03:47 xdg-desktop-portal-gnome: Failed to associate portal window
with parent window
Jan 16 09:03:52 gnome-shell: Error blitting to screencast framebuffer:
cogl_framebuffer_blit premult mismatch.
Jan 16 09:03:52 gnome-shell: Could not destroy EGLImage attached to GBM BO: One
or more argument values are invalid.
[Above two errors repeat ~50+ times before crash]
```
## Stack Trace (top)
```
__pthread_kill_implementation (threadid=<optimized out>, signo=11, no_tid=0) at
./nptl/pthread_kill.c:44
__pthread_kill_internal (threadid=<optimized out>, signo=11) at
./nptl/pthread_kill.c:89
__GI___pthread_kill (threadid=<optimized out>, signo=signo@entry=11) at
./nptl/pthread_kill.c:100
__GI_raise (sig=11) at ../sysdeps/posix/raise.c:26
```
## Related Bugs
- Ubuntu Bug #2069565 - Similar framebuffer blit crash
- GNOME Mutter #21 - GBM BO null pointer crash on hybrid GPU
- GNOME Mutter #2060 - Crash when docking with Intel Xe
## Analysis
The crash appears to be triggered by:
1. Screen capture request via xdg-desktop-portal
2. Mesa Intel driver warning about YUV colorspace + DRM modifiers
3. Screencast portal fails to start properly
4. Cogl framebuffer blit operation fails with premultiplied alpha mismatch
5. EGLImage destruction fails repeatedly
6. Eventually corrupts GPU state causing SIGSEGV
** Affects: mutter (Ubuntu)
Importance: Undecided
Status: New
** Tags: crash intel meteor-lake pipewire screencast wayland
** Attachment added: "gnome-shell-crash.crash"
https://bugs.launchpad.net/bugs/2138507/+attachment/5939498/+files/gnome-shell-crash.crash
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https://bugs.launchpad.net/bugs/2138507
Title:
gnome-shell crash during screencast: cogl_framebuffer_blit premult
mismatch on Intel Meteor Lake
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