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

[Luben Tuikov]

On 2022-10-18 23:37, Luben Tuikov wrote:
> 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.

Also, don't forget to CC stable (by a tag in the commit description).

Regards,
Luben

> 
> 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;
>>  	}
>>