[PATCH 3/5] mm: Add kmalloc NULL tests

Julia Lawall
2009-07-30T14:10:22Z

From: Julia Lawall <julia@diku.dk>

Check that the result of kmalloc is not NULL before passing it to other
functions.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression *x;
identifier f;
constant char *C;
@@

x = \(kmalloc\|kcalloc\|kzalloc\)(...);
... when != x = NULL
when != x != NULL
when != (x || ...)
(
kfree(x)
|
f(...,C,...,x,...)
|
*f(...,x,...)
|
*x->f
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
mm/slab.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 7b5d4de..972e427 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1502,6 +1502,7 @@ void __init kmem_cache_init(void)

ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);

+ BUG_ON(!ptr);
BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
memcpy(ptr, cpu_cache_get(&cache_cache),
sizeof(struct arraycache_init));
@@ -1514,6 +1515,7 @@ void __init kmem_cache_init(void)

ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);

+ BUG_ON(!ptr);
BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
!= &initarray_generic.cache);
memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),