Re: [Xenomai-help] rt_task_join() call hangs in shared lib destructor

[Mauro Salvini <mauro.salvini@domain.hid>]

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> It looks like a typical pthread_join deadlock. The thread you are 
> joining is locked on a pthread mutex, that some other thread (I would 
> say, the one calling pthread_join) has. It can not work. You should not 
> call pthread_join while holding a mutex. 

Yes, it looks like this, but I don't use any mutex in my task. It looks like dlclose() locks a mutex used also by pthread_join() (that was called into shared object destructor), and here is deadlock. But executing realtime task as normal thread does not raise this issue. 

Another strange behaviour: if task was not created with rt_task_create()-rt_task_start(), but becomes real time from a thread with rt_task_shadow(), it works properly. 

Summarizing: 
- create task with rt_task_create()-rt_task_start() and join it in shared object destructor with rt_task_join() -> deadlock 
- create a thread with pthread_create(), make it real-time with rt_task_shadow() and join it in destructor with rt_task_join() -> works fine 
- create a thread with pthread_create(), join it in destructor with pthread_join() -> works fine 

Same behaviors on kernel 2.6.37 with Xenomai 2.5.6 Ipipe 2.9-00 . 

> If this is not the issue, would you please take the time to post a 
> self-contained test case which I can run to reproduce the issue? 

Was attached on my first mail, I re-attach it to this mail. I also added 2nd and 3rd case explained above: you can select each case with three #defines into TestMod.c. 

Many thanks, regards. 


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