Deadlock when using shmsrc+decodebin+videomixer

Submitted by Sean-Der

Link to original bug (#775495)

Description

Created attachment 341182
source code

I have a long running parent process that consumes mkv from multiple temporary processes using shmsrc and then combines them via videomixer. If there is a better way to do this I would love to hear as well. I also am not sure which element is the culprit for the bug, if you swap/remove any of them the issues doesn't happen.

Sometimes when the parent process is overloaded it will deadlock. I am able to reproduce the deadlock by creating an artificial pause in the handoff of an identity. Once the fpsdisplaysink stops printing I can attach via gdb and see where everything is stuck.

I have attached the source code and the bt

The shmsink for the example is
gst-launch-1.0 videotestsrc ! matroskamux ! shmsink wait-for-connection=true socket-path=/tmp/foobar

Attachment 341182, "source code":
code.c