[PATCH] Revert "mm/slub: fix a memory leak in sysfs_slab_add()"

[Wang Hai]

This reverts commit dde3c6b72a16c2db826f54b2d49bdea26c3534a2.

syzbot report a double-free bug. The following case can cause this bug.
 - mm/slab_common.c: create_cache(): if the __kmem_cache_create()
fails, it does:

	out_free_cache:
		kmem_cache_free(kmem_cache, s);

 - but __kmem_cache_create() - at least for slub() - will have done

	sysfs_slab_add(s)
		-> sysfs_create_group() .. fails ..
		-> kobject_del(&s->kobj); .. which frees s ...

We can't remove the kmem_cache_free() in create_cache(), because
other error cases of __kmem_cache_create() do not free this.

So, revert the commit dde3c6b72a16 ("mm/slub: fix a memory leak in
sysfs_slab_add()") to fix this.

Reported-by: syzbot+d0bd96b4696c1ef67991@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: dde3c6b72a16 ("mm/slub: fix a memory leak in sysfs_slab_add()")
Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx>
---
 mm/slub.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 69742ab9a21d..7ecbbbe5bc0c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5625,10 +5625,8 @@ static int sysfs_slab_add(struct kmem_cache *s)
 
 	s->kobj.kset = kset;
 	err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
-	if (err) {
-		kobject_put(&s->kobj);
+	if (err)
 		goto out;
-	}
 
 	err = sysfs_create_group(&s->kobj, &slab_attr_group);
 	if (err)
-- 
2.17.1