Re: [PATCH] platform/x86: hp-bioscfg: Fix error handling in hp_add_other_attributes()

[Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>]

Hi Hans,
On 10/11/23 4:50 pm, Hans de Goede wrote:
> Hi Harshit,
>
> On 11/10/23 10:04, Harshit Mogalapalli wrote:
> > 1. acpi_object *obj is unused in this function, so delete it, also
> >     delete a unnecessary kfree(obj);
> > 2. Fix a memory leak of 'attr_name_kobj' in the error handling path.
> > 3. When kobject_init_and_add() fails on every subsequent error path call
> >     kobject_put() to cleanup.
>
> If you are fixing 3 different things, please do so in a series
> of 3 patches each addressing 1 of the 3 things.

Issue 1 is solved by cleaning up obj, so that can be in patch 1.
Issue 2 & 3 are solved by using a kobj_put(which also takes care of 
kfree()) correctly before returning on an error path, so issue 2,3 will 
have a same fix. This can be done in patch 2.

I will send a V2 with splitting the patches.

Thanks,
Harshit

> Regards,
>
> Hans
>
>
>
> > Fixes: a34fc329b189 ("platform/x86: hp-bioscfg: bioscfg")
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Reported-by: Dan Carpenter <error27@xxxxxxxxx>
> > Closes: https://lore.kernel.org/r/202309201412.on0VXJGo-lkp@xxxxxxxxx/
> > Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
> > ---
> > This is only compile tested, based on static analysis.
> > ---
> >   drivers/platform/x86/hp/hp-bioscfg/bioscfg.c | 14 ++++++--------
> >   1 file changed, 6 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> > index 5798b49ddaba..b28e52b64690 100644
> > --- a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> > +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.c
> > @@ -588,7 +588,6 @@ static void release_attributes_data(void)
> >   static int hp_add_other_attributes(int attr_type)
> >   {
> >   	struct kobject *attr_name_kobj;
> > -	union acpi_object *obj = NULL;
> >   	int ret;
> >   	char *attr_name;
> >   
> > @@ -596,8 +595,8 @@ static int hp_add_other_attributes(int attr_type)
> >   
> >   	attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
> >   	if (!attr_name_kobj) {
> > -		ret = -ENOMEM;
> > -		goto err_other_attr_init;
> > +		mutex_unlock(&bioscfg_drv.mutex);
> > +		return -ENOMEM;
> >   	}
> >   
> >   	/* Check if attribute type is supported */
> > @@ -614,15 +613,15 @@ static int hp_add_other_attributes(int attr_type)
> >   
> >   	default:
> >   		pr_err("Error: Unknown attr_type: %d\n", attr_type);
> > -		ret = -EINVAL;
> > -		goto err_other_attr_init;
> > +		kfree(attr_name_kobj);
> > +		mutex_unlock(&bioscfg_drv.mutex);
> > +		return -EINVAL;
> >   	}
> >   
> >   	ret = kobject_init_and_add(attr_name_kobj, &attr_name_ktype,
> >   				   NULL, "%s", attr_name);
> >   	if (ret) {
> >   		pr_err("Error encountered [%d]\n", ret);
> > -		kobject_put(attr_name_kobj);
> >   		goto err_other_attr_init;
> >   	}
> >   
> > @@ -647,10 +646,9 @@ static int hp_add_other_attributes(int attr_type)
> >   
> >   	mutex_unlock(&bioscfg_drv.mutex);
> >   	return 0;
> > -
> >   err_other_attr_init:
> > +	kobject_put(attr_name_kobj);
> >   	mutex_unlock(&bioscfg_drv.mutex);
> > -	kfree(obj);
> >   	return ret;
> >   }
> >