On 10/23/25 17:30, Kuehling, Felix wrote:
>
> On 2025-10-23 03:48, Arunpravin Paneer Selvam wrote:
>> Acked-by: Arunpravin Paneer Selvam <[email protected]>
>>
>> Regards,
>> Arun.
>> On 10/23/2025 12:28 PM, Sunil Khatri wrote:
>>> Due to low memory or when num of pages is too big to be
>>> accomodated, allocation could fail for pfn's.
>>>
>>> Chekc hmm_pfns for NULL before calling the kvfree for the it.
>>>
>>> Signed-off-by: Sunil Khatri <[email protected]>
>>> ---
>>> drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 6 +++++-
>>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>>> index d6f903a2d573..6ac206e2bc46 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
>>> @@ -286,7 +286,11 @@ void amdgpu_hmm_range_free(struct amdgpu_hmm_range
>>> *range)
>>> if (!range)
>>> return;
>>> - kvfree(range->hmm_range.hmm_pfns);
>>> + if (range->hmm_range.hmm_pfns) {
>>> + kvfree(range->hmm_range.hmm_pfns);
>>> + range->hmm_range.hmm_pfns = NULL;
>>> + }
>
> NULL-checks before kfree and friends are unnecessary. There are actually
> static checkers that complain about such unnecessary NULL-checks. For
> example, see https://lkml.org/lkml/2024/8/11/168.
>
> The same is also true for the standard libc free in usermode:
> https://stackoverflow.com/questions/1912325/checking-for-null-before-calling-free.
>
> Finally, setting range->hmm_range.hmm_pfns = NULL is also unnecessary because
> you're about to free the whole range structure anyway.
Agree completely with Felix.
Sunil why do you think that this is necessary and blocking KFD for some reason?
Regards,
Christian.
>
> Regards,
> Felix
>
>
>>> +
>>> amdgpu_bo_unref(&range->bo);
>>> kfree(range);
>>> }
>>
