[Xenomai-help] troubles deleting tasks

[Xenomai-help] troubles deleting tasks

[Philipp Keller]

Hello

We have troubles deleting the main task created with rt_task_shadow()
from user space.
In the course of initiating the program, we spawn two other threads from
the main task with rt_task_spawn().
When ending the application, both the spawned tasks can be deleted with
rt_task_delete(), but the main task returns with an unknown error code
when calling rt_task_delete().
We believe to have released all recources before deleting, closing all
sockets and file handlers.
The trouble is that we cannot initiate rt can socket communication again
after failing to delete the main thread.
Doeas anyone have an idea what the probelm may be here?

Thanks for any hint
Philipp

 
-- 
Philipp Keller
Software Development

Neuronics AG
Technoparkstrasse 1
8005 Zuerich / Switzerland
Tel +41 44 445 16 40
Fax +41 44 445 16 44
www.neuronics.ch
-- 

Re: [Xenomai-help] troubles deleting tasks

[Philippe Gerum]

On Fri, 2006-11-10 at 14:17 +0100, Philipp Keller wrote:
> Hello
> 
> We have troubles deleting the main task created with rt_task_shadow()
> from user space.
> In the course of initiating the program, we spawn two other threads from
> the main task with rt_task_spawn().
> When ending the application, both the spawned tasks can be deleted with
> rt_task_delete(), but the main task returns with an unknown error code
> when calling rt_task_delete().

Knowing which error code would help.

> We believe to have released all recources before deleting, closing all
> sockets and file handlers.
> The trouble is that we cannot initiate rt can socket communication again
> after failing to delete the main thread.
> Doeas anyone have an idea what the probelm may be here?
> 
> Thanks for any hint
> Philipp
> 
>  
> -- 
> Philipp Keller
> Software Development
> 
> Neuronics AG
> Technoparkstrasse 1
> 8005 Zuerich / Switzerland
> Tel +41 44 445 16 40
> Fax +41 44 445 16 44
> www.neuronics.ch
-- 
Philippe.

Re: [Xenomai-help] troubles deleting tasks

[Philippe Gerum]

On Fri, 2006-11-10 at 14:31 +0100, Philippe Gerum wrote:
> On Fri, 2006-11-10 at 14:17 +0100, Philipp Keller wrote:
> > Hello
> > 
> > We have troubles deleting the main task created with rt_task_shadow()
> > from user space.
> > In the course of initiating the program, we spawn two other threads from
> > the main task with rt_task_spawn().
> > When ending the application, both the spawned tasks can be deleted with
> > rt_task_delete(), but the main task returns with an unknown error code
> > when calling rt_task_delete().
>
> Knowing which error code would help.
> 

The following frag definitely works (i.e. the second printf() is not
issued because the current task has been deleted in the meantime), even
if using rt_task_self() for getting back the current task handle over
the main context, so there must be something else going on with your
application. Again, telling us the _exact_ error code value you get from
rt_task_delete() is the only way to start investigating the issue;
knowing that you apparently tested all the documented return codes in
your program does _not_ tell us which value is actually returned, and
therefore won't help much.

#include <stdio.h>
#include <sys/mman.h>
#include <native/task.h>

RT_TASK task;

int main(int ac, char **av)
{
        mlockall(MCL_CURRENT|MCL_FUTURE);

        printf("rt_task_create=%d\n",
               rt_task_shadow(&task, "task", 50, 0));

        printf("rt_task_delete=%d\n",
                rt_task_delete(&task));

        return 0;
}


> > We believe to have released all recources before deleting, closing all
> > sockets and file handlers.
> > The trouble is that we cannot initiate rt can socket communication again
> > after failing to delete the main thread.
> > Doeas anyone have an idea what the probelm may be here?
> > 
> > Thanks for any hint
> > Philipp
> > 
> >  
> > -- 
> > Philipp Keller
> > Software Development
> > 
> > Neuronics AG
> > Technoparkstrasse 1
> > 8005 Zuerich / Switzerland
> > Tel +41 44 445 16 40
> > Fax +41 44 445 16 44
> > www.neuronics.ch
-- 
Philippe.

Re: [Xenomai-help] troubles deleting tasks

[Jan Kiszka]

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Philipp Keller wrote:
> Hello
> 
> We have troubles deleting the main task created with rt_task_shadow()
> from user space.

https://mail.gna.org/public/xenomai-help/2006-11/msg00077.html ???

Jan


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Re: [Xenomai-help] troubles deleting tasks

[Jan Kiszka]

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Philipp Keller wrote:
> Thank you Jan.
> 
> As to your answer:
> That must be a different issue. Check /proc/xenomai/rtdm/open_fildes for
> any leftover (CAN) file descriptor. Note that rt_dev_close() can fail if
> the descriptor is busy. And such thing can happen if you simply kill the
> task that currently blocks on a CAN device e.g.
> 
> The correct ordering is therefore: close the sockets, catch the failure
> in the blocking threads, and make them self-terminate. Granted, note the
> most comfortable situation, but I'm sure we can improve it in the future
> (e.g. via auto-cleanup also for RTDM file descriptors).
> 
> I am actually doing that quite defensively I think, as you see in the
> code snippet:
[...]

That code looks sane (for UP systems), and you are dumping all errors so
that I can assume a non-closed socket would have been detected.

So we now need more information on your precise issues, which are still
two as I see it: rt_task_delete(&main) (actually a non-issue as I
explained) and the failing re-opening of the CAN device.

What error codes do you get? Can you derive a simple demo program that
exposes the error and can be analysed by us?

Jan


PS: Yet another lacking reply-to-all...


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