Messages in this thread Patch in this message | | | Date | Tue, 1 Jul 2014 09:58:52 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: mm: slub: invalid memory access in setup_object |
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On Mon, 30 Jun 2014, David Rientjes wrote:
> It's not at all clear to me that that patch is correct. Wei?
Looks ok to me. But I do not like the convoluted code in new_slab() which Wei's patch does not make easier to read. Makes it difficult for the reader to see whats going on.
Lets drop the use of the variable named "last".
Subject: slub: Only call setup_object once for each object
Modify the logic for object initialization to be less convoluted and initialize an object only once.
Signed-off-by: Christoph Lameter <cl@linux.com>
Index: linux/mm/slub.c =================================================================== --- linux.orig/mm/slub.c 2014-07-01 09:50:02.486846653 -0500 +++ linux/mm/slub.c 2014-07-01 09:52:07.918802585 -0500 @@ -1409,7 +1409,6 @@ static struct page *new_slab(struct kmem { struct page *page; void *start; - void *last; void *p; int order;
@@ -1432,15 +1431,11 @@ static struct page *new_slab(struct kmem if (unlikely(s->flags & SLAB_POISON)) memset(start, POISON_INUSE, PAGE_SIZE << order);
- last = start; for_each_object(p, s, start, page->objects) { - setup_object(s, page, last); - set_freepointer(s, last, p); - last = p; + setup_object(s, page, p); + set_freepointer(s, p, p + s->size); } - setup_object(s, page, last); - set_freepointer(s, last, NULL); - + set_freepointer(s, start + (page->objects - 1) * s->size, NULL); page->freelist = start; page->inuse = page->objects; page->frozen = 1;
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