[PATCH] drm/amdgpu/discovery: fix possible memory leak

[Luben Tuikov]

On 2022-10-18 04:05, Yang Yingliang wrote:
> If kset_register() fails, the refcount of device is not 0, the name allocated
> in dev_set_name() is leaked. Fix this by calling kset_put(), so that it will
> be freed in callback function kobject_cleanup().
> 

Good catch, but looking at the code it seems that what is being
leaked is the memory pointed to by kset.kobj.name which is allocated
in kobject_set_name(&kset.kobj, ...), which is called right
before the call to kset_register().

Modify the description with this explanation and repost the patch and I'll R-B it then.
Something like:

> If kset_register() fails, the refcount of the device is not 0, and the name allocated
> in kobject_set_name(&kset.kobj, ...) is leaked. Fix this by calling kset_put(),
> so that kset.kobj.name is freed in the callback function kobject_cleanup().

Now, if there's a leak of dev_set_name(), then that would be something
else/another patch.

The rest below looks good.

Since this patch touches only files under drm/amd/amdgpu/ and for a highly AMD-specific
feature, you didn't need to spam the dri-dev ML--amdgfx ML should be plenty enough.

Regards,
Luben

> Fixes: a6c40b178092 ("drm/amdgpu: Show IP discovery in sysfs")
> Signed-off-by: Yang Yingliang <yangyingliang at huawei.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> index 3993e6134914..638edcf70227 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
> @@ -863,7 +863,7 @@ static int amdgpu_discovery_sysfs_ips(struct amdgpu_device *adev,
>  				res = kset_register(&ip_hw_id->hw_id_kset);
>  				if (res) {
>  					DRM_ERROR("Couldn't register ip_hw_id kset");
> -					kfree(ip_hw_id);
> +					kset_put(&ip_hw_id->hw_id_kset);
>  					return res;
>  				}
>  				if (hw_id_names[ii]) {
> @@ -954,7 +954,7 @@ static int amdgpu_discovery_sysfs_recurse(struct amdgpu_device *adev)
>  		res = kset_register(&ip_die_entry->ip_kset);
>  		if (res) {
>  			DRM_ERROR("Couldn't register ip_die_entry kset");
> -			kfree(ip_die_entry);
> +			kset_put(&ip_die_entry->ip_kset);
>  			return res;
>  		}
>  
> @@ -989,6 +989,7 @@ static int amdgpu_discovery_sysfs_init(struct amdgpu_device *adev)
>  	res = kset_register(&adev->ip_top->die_kset);
>  	if (res) {
>  		DRM_ERROR("Couldn't register die_kset");
> +		kset_put(&adev->ip_top->die_kset);
>  		goto Err;
>  	}
>