https://bugs.kde.org/show_bug.cgi?id=524325
Bug ID: 524325
Summary: kwin_wayland crashes with SIGSEGV in
EglContext::pushFramebuffer during screencast under
GPU load
Classification: Plasma
Product: kwin
Version First 6.7.4
Reported In:
Platform: CachyOS
OS: Linux
Status: REPORTED
Severity: crash
Priority: NOR
Component: screencasting
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
Created attachment 195191
--> https://bugs.kde.org/attachment.cgi?id=195191&action=edit
Full backtrace of all threads from coredumpctl dump (SIGSEGV, SEGV_MAPERR)
STEPS TO REPRODUCE
1. Start a fullscreen (entire desktop) screen share via Discord
(xdg-desktop-portal → PipeWire)
2. Run a GPU-intensive application in parallel (reproduced with Factorio)
3. Have a browser (Firefox) open simultaneously
4. Crash occurs after some time under this combined load
OBSERVED RESULT
kwin_wayland crashes with signal 11 (SIGSEGV), si_code SEGV_MAPERR. The screen
goes black briefly, the entire Wayland session is torn down and restarted, and
all running applications are closed as a result.
Backtrace of the crashing thread shows the fault inside:
KWin::EglContext::currentFramebuffer / KWin::EglContext::pushFramebuffer
called from KWin::WorkspaceScene::paint
called from within KWin::ScreenCastStream::record
Several other threads were simultaneously blocked in pthread_cond_timedwait
inside libnvidia-eglcore.so at the time of the crash, suggesting a race
condition under GPU load between the compositor's screencast frame copy and the
NVIDIA driver's EGL backend.
Full backtrace attached (coredumpctl dump output).
EXPECTED RESULT
KWin should continue running without crashing, even under combined GPU load
from screen sharing and a running game. At most, a dropped/skipped screencast
frame would be acceptable — not a full compositor crash that terminates the
entire session.
SOFTWARE/OS VERSIONS
Operating System: CachyOS Linux
KDE Plasma Version: 6.7.4
KDE Frameworks Version: 6.28.0
Qt Version: 6.11.1
Kernel Version: 7.1.8-1-cachyos (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 3700X 8-Core Processor
Memory: 32 GiB of RAM (31.3 GiB usable)
Graphics Processor: NVIDIA GeForce GTX 1660 SUPER
kwin 6.7.4
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