Investigate dead lock of dynamic buffer queue on linux

[rrahn]

An empty dynamic buffer queue seems to dead lock if too many readers are acquiring the shared lock. From some first investigations it seems that the producer thread acquiring the unique lock for the shared mutex is never locking because there are always consumer threads in the shared lock.

Things to further investigate:

• Is the shared mutex in the standard implementation starvation free?
• Are all consumers leaving the shared lock or is there at least one thread always locking the shared lock?
• Is a non shared implementation with a normal mutex and uniqe locks in the consumer section also dead locking?