Pd-0.40 on linux with ALSA severly leaks file-handles when starting/stopping the DSP.
whenever you restart the DSP the /dev/snd/control* devices are opened anew, but none are closed.
this eventually leads to a "too many open files" error, which will keep you from saving your patches (and restarting the DSP)
this appears with Pd-0.40-2
it has been fixed in Pd-0.41 and above
i am just reporting the bug for the sake of completeness.