jack-mixer / jack_mixer

A multi-channel audio mixer desktop application for the JACK Audio Connection Kit.
https://rdio.space/jackmixer/
GNU General Public License v2.0
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Occasional "Segmentation fault" when jackd runs at fps<1024 #169

Open PA3FUN opened 1 year ago

PA3FUN commented 1 year ago

Goodday dear jack_mixer maintainer(s).

Help?! I'm using jack_mixer in an application where low-latency is a must. Platform: Ubuntu 20.04.5 LTS FocalFossa. Jack_mixer: 17. Hardware: Lenovo Tiny M92P (Intel(R) Core(TM) i5-3470T CPU @ 2.90GHz), 4GB RAM, 128GB SSD.

Once every 10 - 15 times jack_mixer is invoked with jackd configured for any value less than fps=1024 jack_mixer crashes upon start-up. When invoked

  1. without a configuration-file (so without the -c ) or
  2. with Jackd running at fps >= 1024 all works well.

When invoked with the "-d" option, the debug-trail shows the following upon an occurring crash: " (jack_mixer:27544): CRITICAL : 11:11:20.025: g_type_info_get_tag: assertion 'GI_IS_TYPE_INFO (info)' failed /usr/lib/python3.8/site-packages/jack_mixer/channel.py:207: Warning: cannot retrieve class for invalid (unclassed) type '(null)' self.volume_digits = Gtk.Entry()" followed by "./cycle_jack_mixer.sh: line 16: 27544 Segmentation fault (core dumped) jack_mixer -d -c $HOME/.local/share/jack_mixer/2ch-mixer.xml"

The problem can be easily reproduced and does not seem to be related to the size of the mixer in terms of number of sliders and/or controls. To reproduce this issue I wrote a small bash- script:

musician@Testbox2:~$ cat cycle_jack_mixer.sh

!/bin/bash

# # jackd -ddummy -p512 -r48000 & sleep 3

jack_mixer & sleep 2 while [ $? = 0 ] do mixer_pid=$(pgrep python3) kill $mixer_pid

jack_mixer -d -c $HOME/.local/share/jack_mixer/2ch-mixer.xml & sleep 2 done

The .xml config-file used: musician@Testbox2:~$ cat 2ch-mixer.xml <?xml version="1.0" ?>

Please note: the issue does not seem to be related to this specific .xml file though.

Any help appreciated!

Christiaan PA3FUN

Addendum February 7: Jack_mix_box, build from the same sources (v 17) using the "-Dgui=disabled" option, shows the same behavior. It too crashes once every 10 - 20 times it is invoked when jackd running at 64fps. With jackd running at 1024 it occasionally crashes too, but apparently less frequent.