Commit 9ef8568b authored by Feng Tang's avatar Feng Tang Committed by Vlastimil Babka
Browse files

mm/slub: Consider kfence case for get_orig_size() 



When 'orig_size' of kmalloc object is enabled by debug option, it
should either contains the actual requested size or the cache's
'object_size'.

But it's not true if that object is a kfence-allocated one, and the
data at 'orig_size' offset of metadata could be zero or other values.
This is not a big issue for current 'orig_size' usage, as init_object()
and check_object() during alloc/free process will be skipped for kfence
addresses. But it could cause trouble for other usage in future.

Use the existing kfence helper kfence_ksize() which can return the
real original request size.

Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
Reviewed-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
parent b6da9401

mm/slub.c

+3 −0
Original line number Diff line number Diff line
@@ -768,6 +768,9 @@ static inline unsigned int get_orig_size(struct kmem_cache *s, void *object) 
{

	void *p = kasan_reset_tag(object);



	if (is_kfence_address(object))

		return kfence_ksize(object);



	if (!slub_debug_orig_size(s))

		return s->object_size;