[PATCH 1/2] drm/radeon: Fix PCI device refcount leak in radeon_atrm_get_bios()

[Lazar, Lijo]

On 11/22/2022 8:19 PM, Alex Deucher wrote:
> On Tue, Nov 22, 2022 at 6:12 AM Xiongfeng Wang
> <wangxiongfeng2 at huawei.com> wrote:
>>
>> As comment of pci_get_class() says, it returns a pci_device with its
>> refcount increased and decreased the refcount for the input parameter
>> @from if it is not NULL.
>>
>> If we break the loop in radeon_atrm_get_bios() with 'pdev' not NULL, we
>> need to call pci_dev_put() to decrease the refcount. Add the missing
>> pci_dev_put() to avoid refcount leak.
> 
> For both patches, I think pci_dev_put() needs to go into the loops.
> There are 2 or more GPUs on the systems where this is relevant.
> 

As per the logic, the loop breaks when it finds a valid ATRM handle. So 
dev_put is required only for that device.

When inside the loop this happens -  "decreased the refcount for the 
input parameter @from if it is not NULL"

Thanks,
Lijo

> Alex
> 
>>
>> Fixes: d8ade3526b2a ("drm/radeon: handle non-VGA class pci devices with ATRM")
>> Fixes: c61e2775873f ("drm/radeon: split ATRM support out from the ATPX handler (v3)")
>> Signed-off-by: Xiongfeng Wang <wangxiongfeng2 at huawei.com>
>> ---
>>   drivers/gpu/drm/radeon/radeon_bios.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpu/drm/radeon/radeon_bios.c b/drivers/gpu/drm/radeon/radeon_bios.c
>> index 33121655d50b..2df6ce3e32cb 100644
>> --- a/drivers/gpu/drm/radeon/radeon_bios.c
>> +++ b/drivers/gpu/drm/radeon/radeon_bios.c
>> @@ -227,6 +227,7 @@ static bool radeon_atrm_get_bios(struct radeon_device *rdev)
>>
>>          if (!found)
>>                  return false;
>> +       pci_dev_put(pdev);
>>
>>          rdev->bios = kmalloc(size, GFP_KERNEL);
>>          if (!rdev->bios) {
>> --
>> 2.20.1
>>