Question about malloc and free

[Joel Sherrill]

Arquer Stephane wrote:
> Hello,
>
> Rtems: 4.7.1
> Bsp: i386-rtems4.7
>
> I've a problem using malloc and free functions, a malloc is used in a
> tool function that return a char* to create a string. The returned
> address is 0x8 which is not a correct one.
>   
There is either a bug in the heap code or you have overwritten
a memory buffer allocated from the heap.  My hunch is that latter.
Turn on RTEMS_DEBUG and that should enable all the heap
consistency checking. 
> Then, a call to free( name_sem ) crash due to
> rtems_region_return_segment(rtems_malloc_heap, ptr);  (malloc.c:487)
>
> I'd like to understand why this malloc return such address ?
>
> I use the following code:
> static int posix_bb_sem_get(S_BB_T *bb, int create){
> 	char* name_sem = NULL;
> 	int oflag = 0;
> 	if (create)
> 		oflag = O_CREAT | O_EXCL;	
>
> 	name_sem = bb_utils_build_sem_name(bb->name);
> 	bb->priv.posix.sem_id = (sem_t *)sem_open(name_sem, oflag |
> BB_SEM_ACCESS_RIGHT);
> 	
> 	if ( bb->priv.posix.sem_id < 0) {
> 		LOG(BB_LOG_SEVERE, "BlackBoard::bb_create",
> 		    "Cannot create semaphore < %s >", name_sem);
> 		goto err;
> 	}
> 	free(name_sem);
> 	return BB_NOK;
> }
>
>
>
> Thanks.
>
> sa
>
> _______________________________________________
> rtems-users mailing list
> rtems-users at rtems.com
> http://rtems.rtems.org/mailman/listinfo/rtems-users
>