Re: [Xenomai-help] Sporadic PC freeze after rt_task_start

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

Hi Jan,

I did another test to identify the freeze. I have plugged in a POST-CODE 80 PCI board into the PC
and instrumented the code to write to port 80 to find out where the freeze actually happens.
It seems not to return for rt_task_start as the last written POST code (see source code below)  is 0x30.
I hope to find a time slot to modify the kernel to do another test.
The bad thing is that it takes really long to get the freeze (up to a couple of hours).

Regards

Mathias

---------------------------------- BEGIN SOURCE CODE -----------------------
#include <stdio.h>
#include <sys/mman.h>
#include <sys/io.h>

#include <native/task.h>
#include <native/sem.h>


RT_TASK taska_desc;

void mytaska(void *cookie)
{
    int i;

    outb(0x80,0x80);

    for (i=0; i < 5; i++)
    {
        rt_task_sleep(5000000);
        outb(0x90,0x80);
        // printf("Task A\n");
    }
    outb(0xa0,0x80);

    // printf("End of task A\n");
}


int main(void)
{
    int i;
    int j;
    ioperm(0x80, 1, 1);
    mlockall(MCL_CURRENT|MCL_FUTURE);

    for (j=0; j < 10000; j++)
        for (i=10; i < 15000; i++)
        {
            outb(0x20, 0x80);
            rt_task_create(&taska_desc, "mytaska", 0, 81, T_JOINABLE | T_FPU | T_CPU(1));
            outb(0x30, 0x80);
            rt_task_start(&taska_desc, &mytaska, NULL);
            outb(0x40, 0x80);
            usleep(1500);
            outb(0x50, 0x80);

            rt_task_join(&taska_desc);
            if ( i % 100 == 0)
                printf("Loop %i %i\n", j,  i);
        }


    return 0;
}
--------------------------- END  -----------------

 
> > Nothing obvious. Leaves us with probable timing differences or the
> > different versions of our setups (I found this over 2.3.2 and trunk).
> 
> My posted issue is a classic race of self-terminating the native task on
> CPU1 vs. remote-terminating it from CPU0. When the latter wins, things
> fall apart. Some solution needs more thoughts.
> 
> Anyway, this issues is most probably unrelated to your bug.
> 
> > 
> > OK, further analysis on your side would be appreciated. E.g. trying the
> > latest release, switching on debug features in Xenomai like the NMI
> > watchdog or nucleus debugging. Also, nailing down what service call
> > precisely locks up (the join, the termination of the task, etc.) would
> > be good to reduce the search space.
> > 
> 
> As you posted in a different mail, recent versions make no difference.
> Could you now switch on the watchdog and nucleus debugging?
> 
> Thanks,
> Jan
> 
> 
> 

-- 
Mathias Koehrer
mathias_koehrer@domain.hid


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