Re: [PATCH] mm/huge_memory: fix memory leak when kobject_init_and_add() fails

[Lance Yang]

On 2026/6/9 21:19, David Hildenbrand (Arm) wrote:
> On 6/9/26 15:12, ranxiaokai627@xxxxxxx wrote:
> > From: Ran Xiaokai <ran.xiaokai@xxxxxxxxxx>
> >
> > As documented in the comments for kobject_init_and_add():
> >
> > "If this function returns an error, kobject_put() must be called to
> > properly clean up the memory associated with the object.  This is the
> > same type of error handling after a call to kobject_add() and kobject
> > lifetime rules are the same here."
> >
> > This is because kobject_init_and_add() may have already allocated memory
> > internally for the kobject name (kobj->name), and leaving the refcount
> > at 1 prevents its release callback from being triggered.
> >
> > Fixes: 3485b88390b0a ("mm: thp: introduce multi-size THP sysfs interface")
> > Signed-off-by: Ran Xiaokai <ran.xiaokai@xxxxxxxxxx>
> > ---
> >   mm/huge_memory.c | 7 ++-----
> >   1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > index 653f2dc03403..601750dbe79f 100644
> > --- a/mm/huge_memory.c
> > +++ b/mm/huge_memory.c
> > @@ -790,11 +790,8 @@ static struct thpsize *thpsize_create(int order, struct kobject *parent)
> >   
> >   	ret = kobject_init_and_add(&thpsize->kobj, &thpsize_ktype, parent,
> >   				   "hugepages-%lukB", size);
> > -	if (ret) {
> > -		kfree(thpsize);
> > -		goto err;
> > -	}
> > -
> > +	if (ret)
> > +		goto err_put;
> >   
> >   	ret = sysfs_add_group(&thpsize->kobj, &any_ctrl_attr_grp);
> >   	if (ret)
>
> This looks a lot like:
>
> https://lore.kernel.org/all/20260411062152.2092967-1-lgs201920130244@xxxxxxxxx/

Right, the same issue :) There is a v2:

https://lore.kernel.org/linux-mm/20260412175428.2613383-1-lgs201920130244@xxxxxxxxx/

Still pending, though ...