On Fri, 18 Apr 2008 16:56:17 +1000 Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote: > The powerpc kernel stacks need to be naturally aligned, as they > contain the thread info at the bottom, which is obtained by > clearing the low bits of the stack pointer. > > However, when using 64K pages (the stack is smaller than a page), > we use kmalloc to allocate it, which doesn't provide that guarantee. > > It appeared to work so far... until one enables SLUB debugging > which then returns unaligned pointers. Ooops... > > This patch fixes it by using a slab cache with enforced alignment > for those. It replies on my previous patch that adds a > thread_info_cache_init() callback. > > ... > > +void thread_info_cache_init(void) > +{ > + thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE, > + THREAD_SIZE, 0, NULL); > + BUG_ON(thread_info_cache == NULL); > +} so... the "0" defeats all of SLAB_DEBUG_FREE, SLAB_RED_ZONE, SLAB_POISON and SLAB_STORE_USER, if the comment in slab.h is to be believed. Was that overkill? -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html