[PATCH] drm/buddy: Fix alloc_range() error handling code

[Mario Limonciello]

On 2/8/2024 06:06, Arunpravin Paneer Selvam wrote:
> Hi Christian,
> 
> On 2/8/2024 12:27 PM, Christian König wrote:
>> Am 07.02.24 um 18:44 schrieb Arunpravin Paneer Selvam:
>>> Few users have observed display corruption when they boot
>>> the machine to KDE Plasma or playing games. We have root
>>> caused the problem that whenever alloc_range() couldn't
>>> find the required memory blocks the function was returning
>>> SUCCESS in some of the corner cases.
>>>
>>> The right approach would be if the total allocated size
>>> is less than the required size, the function should
>>> return -ENOSPC.
>>>
>>> Gitlab ticket link - 
>>> https://gitlab.freedesktop.org/drm/amd/-/issues/3097

Syntax should be "Closes: $URL"

>>> Fixes: 0a1844bf0b53 ("drm/buddy: Improve contiguous memory allocation")
>>> Signed-off-by: Arunpravin Paneer Selvam 
>>> <Arunpravin.PaneerSelvam at amd.com>
>>> Tested-by: Mario Limonciello <mario.limonciello at amd.com>
>>
>> Acked-by: Christian König <christian.koenig at amd.com>
>>
>> CC: stable.. ?
> I will check and add the stable kernel version.

Should be 6.7.

> 
> Thanks,
> Arun.
>>
>>> ---
>>>   drivers/gpu/drm/drm_buddy.c | 6 ++++++
>>>   1 file changed, 6 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
>>> index f57e6d74fb0e..c1a99bf4dffd 100644
>>> --- a/drivers/gpu/drm/drm_buddy.c
>>> +++ b/drivers/gpu/drm/drm_buddy.c
>>> @@ -539,6 +539,12 @@ static int __alloc_range(struct drm_buddy *mm,
>>>       } while (1);
>>>         list_splice_tail(&allocated, blocks);
>>> +
>>> +    if (total_allocated < size) {
>>> +        err = -ENOSPC;
>>> +        goto err_free;
>>> +    }
>>> +
>>>       return 0;
>>>     err_undo:
>>
>