2003-03-11 14:33:19

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH] fix kmem_cache_size() for new slab poisoning

The new slab poisoning code broke kmem_cache_size(), it now returns
a too large size as the poisoning area after the object is includes.
XFS's kmem_zone_zalloc thus overwrites exactly that area and triggers
the new checks everytime such an object is freed again.

I don't recommend using XFS on BK-current without this patch applied :)


--- 1.68/mm/slab.c Sat Mar 8 23:50:36 2003
+++ edited/mm/slab.c Tue Mar 11 15:15:44 2003
@@ -2041,11 +2041,16 @@

unsigned int kmem_cache_size(kmem_cache_t *cachep)
{
+ unsigned int objlen = cachep->objsize;
+
#if DEBUG
if (cachep->flags & SLAB_RED_ZONE)
- return (cachep->objsize - 2*BYTES_PER_WORD);
+ objlen -= 2*BYTES_PER_WORD;
+ if (cachep->flags & SLAB_STORE_USER)
+ objlen -= BYTES_PER_WORD;
#endif
- return cachep->objsize;
+
+ return objlen;
}

kmem_cache_t * kmem_find_general_cachep (size_t size, int gfpflags)