I tested with bpo kernel 5.2.0-0.bpo.3-rt-amd64 and similar issue.
I notice there's a set_schedul* something message along with "operation
not permitted"... that might provide a hint..
there's no ~/.gsequencer directory made yet, as the stall occurs either
while still scanning ladspa or lv2 plugins.
The point of the stall is random but it occurs during the plugin-scan..
-- terminal text shows the point that it stalls is random..
Sometimes I am able to do Ctl-c, sometimes not and I need to do a hard
shutdown (power button)..
