queue2: Deadlock in Queue2 when music streaming plays long time.
Submitted by Suhwang Kim
Link to original bug (#783675)
Description
A deadlock occurred while accessing one variable in two threads.
This is sometimes issue.
One thread sets the "downstream_may_block" value.
Compares this value with another thread and executes g_cond_wait().
Deadlock occurs at this point.