SLUB: allocate smallest object size if the user asks for 0 bytes
Makes SLUB behave like SLAB in this area to avoid issues....
Throw a stack dump to alert people.
At some point the behavior should be switched back. NULL is no memory as
far as I can tell and if the use asked for 0 bytes then he need to get no
memory.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 30b154c..f8e0c86 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -80,8 +80,12 @@
*/
static inline int kmalloc_index(int size)
{
- if (size == 0)
- return 0;
+ /*
+ * We should return 0 if size == 0 but we use the smallest object
+ * here for SLAB legacy reasons.
+ */
+ WARN_ON_ONCE(size == 0);
+
if (size > 64 && size <= 96)
return 1;
if (size > 128 && size <= 192)
diff --git a/mm/slub.c b/mm/slub.c
index 4a8585b..9d52cce 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1979,7 +1979,7 @@
{
int index = kmalloc_index(size);
- if (!size)
+ if (!index)
return NULL;
/* Allocation too large? */