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

[SeongJae Park]

+ Guangshuo

On Tue, 9 Jun 2026 22:04:16 +0800 Lance Yang <lance.yang@xxxxxxxxx> wrote:

> 
> 
> 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 ...

I added the author of the patch (Guangshuo) to the recipients list of this
mail, because they may better to aware of this.


Thanks,
SJ