[Xenomai] some API about RT_TASK occur Segmentation fault

Philippe Gerum rpm at xenomai.org
Tue Feb 7 16:17:28 CET 2017


On 02/07/2017 03:19 PM, dreamtale90 at 163.com wrote:
> Just now when I compiling xenomai, removed "--enable-pshared"
> configuration option. My demo is normal finally, and print out third
> sentence "enter func ..." without segmentaion fault.

I believe that you are not using the right code. Did you pull the code
from the stable-3.0.x branch as mentioned earlier?

If you did so, you should see this output when passing the --version
switch to your program:

based on Xenomai/mercury v3.0.3 -- #00e3d01 (2017-01-27 10:16:11 +0100)

> Although the question is solved temporarily , but still don't know the
> reason. So I'm still worried about my system environment have some problems.
> 
> Thanks again, best regards.
> 
> 
> 发自网易邮箱大师
> 
>     在2017年02月07日 14:18,dreamtale90 at 163.com
>     <mailto:dreamtale90 at 163.com> 写道:
>     Thank you for help.
>     I had git clone git://git.xenomai.org/xenomai-3.git, compile and
>     install it with:
>         ./scripts/bootstrap
>         ../xenomai-3/configure --with-core=mercury  --enable-smp
>     --enable-pshared --enable-debug=full
>         make install
>     Then run my demo, but the result is the same as before :
>     ----------------------------------------------------------------------------------------------------------
>        0"002.570| WARNING: [main] Xenomai compiled with full debug enabled,
>                                   very high latencies expected
>     [--enable-debug=full]
>     enter func ...
>     enter func ...
>     rt_task_create:
>     ../../../xenomai-3/lib/copperplate/heapobj-pshared.c:452:
>     alloc_block: Assertion `0' failed.
>     Aborted
>     ----------------------------------------------------------------------------------------------------------
>     Yesterday, I add some printf to alloc_block() of heapobj-pshared.c.
>     I found  that segmentaion fault occur when run to the
>     line 455 "++extent->pagemap[pgnum].bcount;" . At this time the value
>     of "heap->buckets[ilog].freelist" is very big.
> 
>     Now I think whether my xenomai
>     configuration or system environment have something wrong.
>     Besides, my system(x86_64bit) run in a 8 cores Oracle virtual
>     machine, the host cpu is Inter(R) xeon(R) CPU E5-2630 v4 @ 2.20GHz.
>     I don't know whether these information is useful.
> 
>     Thanks in advance, best regards.
> 
> 
> 
>     At 2017-02-06 21:50:13, "Philippe Gerum" <rpm at xenomai.org <mailto:rpm at xenomai.org>> wrote:
>     >On 02/06/2017 02:30 AM, dreamtale90 at 163.com <mailto:dreamtale90 at 163.com> wrote:
>     >> System configuration:
>     >> debian-8.6, 3.18.46-rt50
>     >> Xenomai/mercury v3.0.3
>     >> Build args: --with-core=mercury --enable-smp --enable-pshared
>     >> 
>     >> Now I am need help. Thanks.
>     >> 
>     >> 
>     >> -------- Forwarding messages --------
>     >> From: "dreamtale90 at 163.com <mailto:dreamtale90 at 163.com>" <dreamtale90 at 163.com <mailto:dreamtale90 at 163.com>>
>     >> Date: 2017-02-04 12:04:15
>     >> To: xenomai at xenomai.org <mailto:xenomai at xenomai.org>
>     >> Subject: some API about RT_TASK occur Segmentation fault
>     >> Hi
>     >>     During using API about RT_TASK I found some doubt.
>     >> 1) rt_task_inquire(RT_TASK * task, RT_TASK_INFO * info ), if info is
>     >> NULL will occur Segmentation fault, but in API reference this is valid.
>     >> http://www.xenomai.org/documentation/xenomai-3/html/xeno3prm/group__alchemy__task.html#ga53bad6acf5496f8008e594954507dce8
>     >> 
>     >> 2) After main task called rt_task_shadow(), program will create other
>     >> tasks depend on request, but when create second task will  occur
>     >> Segmentation fault.
>     >> Now main task don't call  rt_task_shadow(), program will OK. I don't
>     >> know why.
>     >> 
>     >> 3) I write a demo which create the same task three times as follows:
>     >> #include <stdio.h>
>     >> #include <unistd.h>
>     >> #include <alchemy/task.h>
>     >> RT_TASK task1;
>     >> void func(void *arg)
>     >> {
>     >>  printf("enter func ...\n");
>     >> }
>     >> int main()
>     >> {
>     >>  rt_task_spawn(&task1, "task1", 0, 80, 0, func, NULL);
>     >>  sleep(1);
>     >>  rt_task_spawn(&task1, "task1", 0, 80, 0, func, NULL);
>     >>  sleep(1);
>     >>  rt_task_spawn(&task1, "task1", 0, 80, 0, func, NULL);
>     >>  //rt_task_delete(&task1);
>     >>  return 0;
>     >> }
>     >> 
>     >> When the third time create , program will  occur Segmentation fault.
>     >> 
>     >
>     >This bug was fixed in the stable branch some time ago:
>     >git://git.xenomai.org/xenomai-3.git, branch stable-3.0.x
>     >
>     >-- 
>     >Philippe.
> 
> 
> 
>      
> 


-- 
Philippe.



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