iOS 15.4 Frida 15.1.17 Cannot Attach to Frontmost App

[pachoo]

This is an FYI in case others have noticed this, or there's something I'm missing.

I noticed that with my iOS device (non jailbroken) at 15.4.1 (haven't tested 15.4) that Frida can no longer attach to the fronstmost application. e.g.

$ frida -U -F
     ____
    / _  |   Frida 15.1.17 - A world-class dynamic instrumentation toolkit
   | (_| |
    > _  |   Commands:
   /_/ |_|       help      -> Displays the help system
   . . . .       object?   -> Display information about 'object'
   . . . .       exit/quit -> Exit
   . . . .
   . . . .   More info at https://frida.re/docs/home/
   . . . .
   . . . .   Connected to iPad (id=xxxx)
No frontmost application on iPad  

Looking into this a bit further, it looks like the problem (for my environment at least, if not all) is that the Instruments deviceinfo service on the device s no longer returning the the "foregroundRunning" in the dictionary for the results from "runningProcesses" for the process running in the foreground.

I haven't looked further into the root cause for this behavioral difference (e.g. functionality removed from instruments) or if it's worth investigating alternate methods to get at this infomration.

Device Info: iPad (iPad5,3, J81AP) running iOS 15.4.1, non JBed.