SUMMARY

When window previews are shown (e.g. by hovering over the task bar or operating Alt-Tab), and pipewire is restarted, kwin_wayland segfaults.

STEPS TO REPRODUCE
1. Open Konsole, hover over its entry in taskbar
2. systemctl --user restart pipewire.service

OBSERVED RESULT
kwin_wayland crashes with segmentation fault

EXPECTED RESULT
kwin_wayland keeps running, maybe the window previews disappear or flicker

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.21.1
KDE Frameworks Version: 5.79.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
When the window preview is shown, kwin_wayland starts another thread. This thread exits before the main thread receives SIGSEGV. Unfortunately, this extra thread seems to have caused memory errors affecting the main thread, since the stack trace seems very corrupted.

The crash is always reproducible.

(ins)(gdb) bt
#0  0x00007f33c1573610 in  ()
#1  0x0000000002827758 in  ()
#2  0x0000000002827758 in  ()
#3  0x0000000000000000 in  ()