Trouble with l4rm_region_cache slab

Hi, I got an application which crashes into slab_alloc (slab.c:358). After some investigation, I've found the faulty slab : l4rm_region_cache. slabs_part != NULL, free_objs == NULL and num_free == 2. My first question is : do you agree this state should not happen ? If yes, I've got the following solutions : 1. there's a bug in slab library, 2. there's a bug in l4rm grow function, 3. synchro problem. It don't believe in 1 or 3. But, in fact, I don't understand l4rm grow mechanism. Another info : one of the analysed crash happened into l4thread_create. Regards Marc