[Xenomai-help] Re: A fairly small rtnet/Xenomai application that freezes the

["M. Koehrer" <mathias_koehrer@domain.hid>]

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Hi Jan, hi everybody,

I have stripped down my program that is crashing Xenomai even further.
(I have attached the complete source code).
No rtnet is required.
Now I have the following real time task:

static void realtimetask(void *arg)
{
    system("ls -l");
    rt_task_sleep(1000000000ULL);
    printf("rt_task_sleep done...\n");
}

This leads to a complete freeze of the PC on a 2.6.19.1 kernel using the latest
Xenomai (from SVN) and the included adeos-patch.
I never had this issue on 2.6.17.* kernel.

Unfortunately this seems to occur only on fast Pentium 4 machines...
Is there anybody out there that can reproduce it?

Thanks for all feedback on this!

Mathias

> > meanwhile I have done a couple of additional tests.
> > With one of the PCs I have, I have disabled the Memory Cache to slow it
> down.
> > The effect was the very same. 
> > I have reproduced the behaviour on another PC (also P4, but different
> mainboard).
> > The system freezes as well.
> > And finally, I have found out that printing out a line with printf()
> directly after the system() call provides
> > a workaround.Then the system is stable.
> > 
> > I have replaced the system() call where I called rtroute with a simple
> call to "ls -l" (i.e system("ls -l") ).
> > Then the system freezes as well.
> > It looks to me as if a system() call out of the realtime task is not
> properly handled.
> > An printf() after the system() call seems to move the system back on
> track...
> > 
> > Hope that helps a little bit to identify the issue...
> 
> Unfortunately not yet. I tried with exactly the same configuration you
> once mailed on a Pentium M 1.3 GHz - but all worked fine. The obvious
> differences are the CPU speed (I may have access to a crash box with
> more GHz next week) and the NIC (rt_eepro100 in my case).
> 
> As my hope of being able to reproduce it on my own is not that high, I
> would like to ask you to try nailing down the lock-up on kernel level.
> That means trying to identify (via printk e.g. - if this doesn't make
> the bug jump around) which function is still executed and where we do
> not get.
> 
> TIA,
> Jan


-- 
Mathias Koehrer
mathias_koehrer@domain.hid


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