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 ?
--
Gilles Chanteperdrix
Index: ksrc/nucleus/pod.c
===================================================================
--- ksrc/nucleus/pod.c (révision 2293)
+++ ksrc/nucleus/pod.c (copie de travail)
@@ -1398,7 +1398,7 @@
and return immediately. Note: a relaxed shadow never has
the KICKED bit set, so that xnshadow_relax() is never
prevented from blocking the current thread. */
- if (xnthread_test_info(thread, XNKICKED)) {
+ if (xnthread_test_info(thread, XNKICKED) && !xnthread_test_info(thread, XNRELAX)) {
xnthread_clear_info(thread, XNRMID | XNTIMEO);
xnthread_set_info(thread, XNBREAK);
if (wchan)
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