Re: [Jack-Devel] Lock recursion in Trylock()

Right: messages removed, commited on my local branch, will push soon.

Stéphane 

Le 10 déc. 2012 à 14:46, MONTANARO Luciano (MM) a écrit :

> Hi all,
> This is the first time I am writing to the list. I am not sure this is the right place to send patches, just let me know if you prefer the use of a different channel.
> I am using jack in an embedded linux project, and I have had to analyze a crash dump from a (heavily threaded) client application, which failed on the
> Jack_error line in JackPosixMutex.cpp: Trylock().
> 
> The cause of this is that jack_error() will call JackMessageBuffer::AddMessage() which will call Trylock(), which, if the lock is held, will call jack_error(), and the wole sequence will repeat until the stack is exhausted.
> 
> Below is a patch that simply disables the jack_error call for this case. Is it actually an error to call Trylock() from a different thread? This seems more like a copy-paste remnant from the Lock() function. The jack_error() calls in Lock() and Unlock() are probably not a problem, though they make me a bit uncomfortable as well.
> 
> I hope this helps,
> Cheers,
> Luciano
> 
> --- a/posix/JackPosixMutex.cpp
> +++ b/posix/JackPosixMutex.cpp
> @@ -69,7 +69,10 @@ namespace Jack
>                 return false;
>             }
>         } else {
> +           /* Calling jack_error here will recursively call Trylock() if
> +            * multithreaded debugging is active.  Don't do that.
>             jack_error("JackBasePosixMutex::Trylock mutex already locked by thread = %d", current_thread);
> +            */
>             return false;
>         }
>     }
> 
> 
> 
> 
> 
> --
> Luciano Montanaro
> EntryNAV - Audio Software Integrator
> Magneti Marelli Electronic Systems
> Viale Carlo Emanuele II 150, Venaria Reale (To)
> Tel. (+39) 011 6879765
> 
> 
> 
> 
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