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authorDavid Rientjes <rientjes@google.com>2008-12-17 22:09:46 -0800
committerPekka Enberg <penberg@cs.helsinki.fi>2008-12-29 11:40:58 +0200
commit7b8f3b66d9d7e5f021ae535620b9b52833f4876e (patch)
tree0495da27c549f9abd8bcb75c158edf20e35ca711 /mm
parentdfcd3610289132a762b7dc0eaf33998262cd9e20 (diff)
downloadlinux-2.6.34-ux500-7b8f3b66d9d7e5f021ae535620b9b52833f4876e.tar.gz
slub: avoid leaking caches or refcounts on sysfs error
If a slab cache is mergeable and the sysfs alias cannot be added, the target cache shall have its refcount decremented. kmem_cache_create() will return NULL, so if kmem_cache_destroy() is ever called on the target cache, it will never be freed if the refcount has been leaked. Likewise, if a slab cache is not mergeable and the sysfs link cannot be added, the new cache shall be removed from the slab_caches list. kmem_cache_create() will return NULL, so it will be impossible to call kmem_cache_destroy() on it. Both of these operations require slub_lock since refcount of all slab caches and slab_caches are protected by the lock. In the mergeable case, it would be better to restore objsize and offset back to their original values, but this could race with another merge since slub_lock was dropped. Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Diffstat (limited to 'mm')
-rw-r--r--mm/slub.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 704cfa34f9a..d057ceb3645 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3124,8 +3124,12 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
up_write(&slub_lock);
- if (sysfs_slab_alias(s, name))
+ if (sysfs_slab_alias(s, name)) {
+ down_write(&slub_lock);
+ s->refcount--;
+ up_write(&slub_lock);
goto err;
+ }
return s;
}
@@ -3135,8 +3139,13 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
size, align, flags, ctor)) {
list_add(&s->list, &slab_caches);
up_write(&slub_lock);
- if (sysfs_slab_add(s))
+ if (sysfs_slab_add(s)) {
+ down_write(&slub_lock);
+ list_del(&s->list);
+ up_write(&slub_lock);
+ kfree(s);
goto err;
+ }
return s;
}
kfree(s);