On Tue, 2007-03-13 at 16:25 +0100, Gilles Chanteperdrix wrote:
> M. Koehrer wrote:
> > Hi all,
> >
> > I have a problem to catch segment violations with Xenomai:
> > For demonstration I use the following program:
> > ------------------------------------------
> > #include <stdio.h>
> > #include <sys/mman.h>
> >
> > #include <native/task.h>
> > #include <native/sem.h>
> > RT_TASK taska_desc;
> > volatile int *pointer = 0;
> >
> > void mytaska(void *cookie)
> > {
> > int i;
> > for (i=0; i < 50; i++)
> > {
> > rt_task_sleep(50000000);
> > if (i > 20)
> > {
> > *pointer = 123;
> > }
> > printf("Hello %i\n", i);
> > }
> > printf("Hi, this is task A\n");
> > }
> >
> > int main(void)
> > {
> > mlockall(MCL_CURRENT|MCL_FUTURE);
> >
> > rt_task_create(&taska_desc, "mytaska", 0, 81, T_JOINABLE);
> > rt_task_start(&taska_desc, &mytaska, NULL);
> >
> > rt_task_join(&taska_desc);
> > printf("Main: A joined\n");
> >
> > return 0;
> > }
> > ---------------------------------------
> > Whenever i is greater than 20 a segment violation occurs, as I must not
> > write
> > to address 0 (the pointer is always NULL).
> > However, what happens is, that my system freezes after printing out 18 or
> > 19.
> > I have to reset the PC to continue.
> > When I write a printf() directly before the invalid assignment I get the
> > usual linux
> > "segmentation fault" error message.
> >
> > How can I catch a signal in a Xenomai real time task?
> >
> > I am running Xenomai 2.3.0 + NOCOW patch.
> >
> > I have enclosed the .c file and a Makefile in a .tgz file.
> >
> > Thanks for any feedback on that issue
>
> It looks like the "relaxing a kicked thread" issue again. Could you try
> the attached patch ?
>
Gasp. This patch would contradict what's going on into
do_sigwake_event(); well, if you are right, we would have entered the
twilight zone with full ignition of the auxiliary boosters.
Btw, XNRELAX is a state bit, not an information one. i.e.
- if (xnthread_test_info(thread, XNKICKED)) {
+ if (xnthread_test_info(thread, XNKICKED) &&
!xnthread_test_state(thread, XNRELAX)) {
--
Philippe.
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