pcm_plug.c:67: snd_pcm_plug_close: Assertion `plug->gen.slave == plug->req_slave' failed

Question

I'm using ALSA for the first time and am seeing the error:

pcm_plug.c:67: snd_pcm_plug_close: Assertion `plug->gen.slave == plug->req_slave' failed.

This occurs when I attempt to close the PCM:

snd_pcm_close(pcm);

What could be causing this error?

Answer 1

It turned out that I was inadvertently calling snd_pcm_close twice. Removing the second call fixed the failure.