Re: [Xenomai-help] Question about rtdm_mmap_to_user()

[Philippe Gerum <rpm@xenomai.org>]

Perrine Martignoni wrote:
>>Mixing up RTDM and native API usage, though technically feasible, isn't
> a good idea anyway. Better have a look at Hannes' example, >and if that
> one or your own version still doesn't work, post more details (Xenomai
> version, target architecture, test code, etc.).
> 
> I found an example in Native-API-Tour.pdf which do this. I try to follow
> it and it doesn't work.
>

Except that the example listed in the document in question takes care of
defining the heap descriptor in global memory, not in the init_module() stack.

> static int dmem_Init(void)
> {   
>         RT_HEAP Heap;

^^^^ this won't survive long enough.

>         int ret =0;
>         void *p_HeapMem = NULL;
> ----------------------------------------------------------------------------------------------------------------------------------
> 
> I see in /proc/xenomai/registry/native/heaps the /HeapTest  /I create.
> And I see that :
> 
> * type=kernel:size=3017801728:used=1
>

i.e. we see a 2.8+ _gigabyte_ heap from which 1 single byte would be in use...,
albeit you defined a 2Kb heap initially, to be used as a single contiguous
segment. Getting braindamage values like this when looking at the /proc
interface should ring a bell about a possible corruption of some important
kernel-based information, like a heap descriptor.

-- 
Philippe.