One thread blocks in pthread_cond_wait, another thread signals the condition
variable and immediatley afterwards cancels the first thread.
A new thread blocking on the same condition variable can't be woken up with
remark: pthread_cond_timedwait shows the same behaviour
workaround: if pthread_cond_broadcast is used instead of pthread_cond_signal,
The attached testcase is a try to make a minimal example, the situation
occurred in a large C++ project.
In this project there are three threads with different realtime priorities
involved (one waites, one signals and one cancels).
Linux 18.104.22.168 #1 PREEMPT Mon Jul 10 15:39:46 CEST 2006 i686 i686 i386 GNU/Linux
glibc 2.3.5 (productive system) also: glibc 2.3.6 and glibc 2.4