Re: [Jack-Devel] Jack thread cancellation

You should never, ever, ever rely on pthread cancellation. Not on any
platform, not for any purpose.


On Fri, May 3, 2013 at 11:11 AM, MONTANARO Luciano (MM) <
[hidden]> wrote:

> Hi list,
>
> I have an embedded application that makes use of jack (Version 1.9.8).
> I have started seeing crashes from the clients in the JackError() call.
>
> The stack trace shows that the thread executing (Which is handling the
> JackSocketChannel::Execute call) receives is being killed
> (sigcancel_handler is called) and since the thread is in
> CANCEL_ASYNCHRONOUS mode, it crashes since an unsafe function is
> called (vnsprintf).
>
> The client I am using is actually unaware of using Jack at all, it is
> using the alsa jack plugin, and it opens/closes the alsa devices many
> times during its lifetime.
>
> Now, I have a few doubts:
> - Why are threads created with cancellation type
> PTHREAD_CANCEL_ASYNCHRONOUS?
>   Is this because the realtime threads need this or is there some other
> reason?
> - Would it be possible to mark the threads used by the JackMessageBuffer
> and
>   JackSocketClientChannel as PTHREAD_CANCEL_DELAYED instead?
> - Why is fThread.Kill() used in JackSocketClientChannel::Stop instead of
> fThread.Stop()?
>   The latter should still work, and allow the Execute() to terminate it
> communication
>   with the server.
>
> Thanks in advance,
> Luciano
> --
> Luciano Montanaro
> EntryNAV - Audio Software Integrator
> Magneti Marelli Electronic Systems
> Viale Carlo Emanuele II 150, Venaria Reale (To)
> Tel. (+39) 011 6879765
>
>
>
>
>
> VISITA IL NOSTRO NUOVO SITO WEB! - VISIT OUR NEW WEB SITE!
> www.magnetimarelli.com
>
> Confidential Notice: This message - including its attachments - may
> contain proprietary, confidential and/or legally protected information and
> is intended solely for the use of the designated addressee(s) above. If you
> are not the intended recipient be aware that any downloading, copying,
> disclosure, distribution or use of the contents of the above information is
> strictly prohibited.
> If you have received this communication by mistake, please forward the
> message back to the sender at the email address above, delete the message
> from all mailboxes and any other electronic storage medium and destroy all
> copies.
> Disclaimer Notice: Internet communications cannot be guaranteed to be safe
> or error-free. Therefore we do not assure that this message is complete or
> accurate and we do not accept liability for any errors or omissions in the
> contents of this message.
> 
> Jack-Devel mailing list
> [hidden]
> http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org
>

1367594606.2807_0.ltw:2,a <CAFa_cK=fEf8J4598wJfe2iTvfBiTZJFoi3a59gxvFBgvhiDU3A at mail dot gmail dot com>