wf-panel-pi intermittently retains X11 application processes in zombie state

[qrp73]

Occasionally, X11 application processes remain in a zombie state, with wf-panel-pi as the parent process. This issue occurs intermittently, preventing the proper cleanup of these zombie processes.

$ uname -a
Linux raspi 6.6.51+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.51-1+rpt2 (2024-10-01) aarch64 GNU/Linux

$ ps -p 134229 -o pid,ppid,stat,cmd
    PID    PPID STAT CMD
 134229    1215 Z    [sdrpp] <defunct>

$ ps -p 1215 -o pid,ppid,stat,cmd
    PID    PPID STAT CMD
   1215    1179 Sl   wf-panel-pi

$ kill -SIGCHLD 1215

$ ps -p 134229 -o pid,ppid,stat,cmd
    PID    PPID STAT CMD
 134229    1215 Z    [sdrpp] <defunct>

$ kill 1215

$ ps -p 134229 -o pid,ppid,stat,cmd
    PID    PPID STAT CMD

If I remember correctly the issue occurs when this app process freezes in a file reading loop due to the file being rewritten by another process. After killing the frozen application from gnome-system-monitor, the process remains in a zombie state.

I occasionally observe this bug from time to time.