mm/slub: release kobject if kobject_init_and_add failed in sysfs_slab_add
Subsystems (2)
PATCH 1/1 mm/slub: release kobject if kobject_init_and_add failed in sysfs_slab_add
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 of s->kobj is leaked.
--- mm/slub.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
mm/slub.c +3 -4
@@ -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); - goto out; +return err; }void sysfs_slab_unlink (struct kmem_cache *s)
Signature · 1 line
2.31.0
Quoted 3 lines · Xin Hao
In
kobject_init_and_add()function, the refcount is setted by callingkobject_init()function, regardless of whether the return value is zero or not, therefore, we must callkobject_del(&s->kobj)to prevent memory
Hello and thanks!
Should kobject_del() be called when kobject_add() failed?
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.
Quoted 36 lines
of
s->kobjis leaked.Signed-off-by Xin Hao <[email protected]>--- mm/slub.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)mm/slub.c +3
-4@@ -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); - goto out; +return err; }void sysfs_slab_unlink (struct kmem_cache *s)Signature · 1 line
2.31.0
Quoted 7 lines · Hyeonggon Yoo
Quoted 3 lines · Xin Hao
In
kobject_init_and_add()function, the refcount is setted by callingkobject_init()function, regardless of whether the return value is zero or not, therefore, we must callkobject_del(&s->kobj)to prevent memoryHello and thanks!
Should
kobject_del()be called whenkobject_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, ...)
Quoted 45 lines
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 whenkobject_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.Quoted 18 lines
of
s->kobjis leaked.Signed-off-by Xin Hao <[email protected]>--- mm/slub.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)mm/slub.c +1
-1@@ -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;
Quoted 11 lines
mm/slub.c static int sysfs_slab_add(struct kmem_cache *s) · line 5994
Quoted 11 lines
mm/slub.c +1
-2if (!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.
Quoted 7 lines
Quoted 7 lines
mm/slub.c +1
-1- goto out; +return err; }void sysfs_slab_unlink (struct kmem_cache *s)Signature · 1 line
2.31.0