2009-11-27 05:10:34 Ipipe error running a rt task

Michael Löffler (GERMANY)

Message: 82811

Hi,

currently I'm struggling with an quite randomly appearing error resulting in an reboot of the system. The last thing printed to the console before the reboot of the system is this:

Kernel panic - not syncing: BUG!

<4>BUG: failure at kernel/ipipe/core.c:319/__ipipe_restore_root()!

icache_enable

I'm running 2008-stable with the xenomai patch. The program itself is running as an rtdm task in the secondary domain and is calling rt_dev_ioctl() in a loop. The device driver itself worked stable so far. Now it sometimes takes several hundred loops, or even several thousand, but then this error happens. I found the corresponding line in the kernel source, but I'm not sure if removing it will cause even worse debuggable problems. Did I forget some special settings in the kernel config or are there some things setting up the rt task, that can go wrong?

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2009-11-27 05:18:17 Re: Ipipe error running a rt task

Yi Li (CHINA)

Message: 82812

Michael,

Could you also report this issue to the xenomai mailing list? Also can you reproduce this bug on 2009R1 release?

-Yi

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2009-11-27 14:25:25 Re: Ipipe error running a rt task

Michael Löffler (GERMANY)

Message: 82817

I put together a little code snippet to demonstrate the error. Unfortunately, I can't test it under 2009R1, as the provided adeos patch does not work for me. As suggested, I'll also have a look at the xenomai list. Here is the snippet. It runs something from 500 to 5000 cycles, and then crashes with the already mentioned error message. The problem seems to be rt_task_sleep(). When I replace it with usleep(), it seems to work fine (10000+ cycles).

#include <stdio.h>

#include <unistd.h>

#include <rtdm/rtdm.h>

#include <native/task.h>

#include <linux/delay.h>

RT_TASK _rtTask;

int main(int argc, char *argv[]) {

rt_task_shadow(&_rtTask, "whatever", 1, 0);

rt_task_set_mode(0, T_PRIMARY, NULL); // primary

uint32_t n = 0;

while (1) {

printf("Loop %u OK. Waiting....\n", n++);