在 2022/8/11 上午11:31, Hyeonggon Yoo 写道:
On Thu, Aug 11, 2022 at 10:52:58AM +0800, Xin Hao wrote:
In kobject_init_and_add() function, the refcount is setted by calling
kobject_init() function, regardless of whether the return value is zero
or not, therefore, we must call kobject_del(&s->kobj) to prevent memory
Hello and thanks!
Should kobject_del() be called when kobject_add() failed?
Yes, I'm afraid think so， you can see the comment about kobject_add()
* Return: If this function returns an error, kobject_put() must be
* called to properly clean up the memory associated with the
* object. Under no instance should the kobject that is passed
* to this function be directly freed with a call to kfree(),
* that can leak memory.
*
* If this function returns success, kobject_put() must also be
called
* in order to properly clean up the memory associated with the
object.
*
* In short, once this function is called, kobject_put() MUST
be called
* when the use of the object is finished in order to properly free
* everything.
*/
int kobject_add(struct kobject *kobj, struct kobject *parent,
const char *fmt, ...)
its comments says:
597 * kobject_del() - Unlink kobject from hierarchy.
598 * @kobj: object.
599 *
600 * This is the function that should be called to delete an object
601 * successfully added via kobject_add().
AFAIK kobject_put() is proper function to call when
kobject_init_and_add() failed as stated in its comment:
417 /**
418 * kobject_init_and_add() - Initialize a kobject structure and add it to
419 * the kobject hierarchy.
420 * @kobj: pointer to the kobject to initialize
421 * @ktype: pointer to the ktype for this kobject.
422 * @parent: pointer to the parent of this kobject.
423 * @fmt: the name of the kobject.
424 *
425 * This function combines the call to kobject_init() and kobject_add().
426 *
427 * If this function returns an error, kobject_put() must be called to
428 * properly clean up the memory associated with the object. This is the
429 * same type of error handling after a call to kobject_add() and kobject
430 * lifetime rules are the same here.
of s->kobj is leaked.
Signed-off-by: Xin Hao <xhao@xxxxxxxxxxxxxxxxx>
---
mm/slub.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index b1281b8654bd..63b0a8a3a71f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5981,19 +5981,18 @@ static int sysfs_slab_add(struct kmem_cache *s)
err = sysfs_create_group(&s->kobj, &slab_attr_group);
if (err)
- goto out_del_kobj;
+ goto out;
if (!unmergeable) {
/* Setup first alias */
sysfs_slab_alias(s, s->name);
}
+ return err;
out:
if (!unmergeable)
kfree(name);
- return err;
-out_del_kobj:
kobject_del(&s->kobj);
Maybe there use kobject_put will be better.
- goto out;
+ return err;
}
void sysfs_slab_unlink(struct kmem_cache *s)
--
2.31.0
