[PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()
Felix Kuehling
felix.kuehling at amd.com
Wed May 1 18:59:35 UTC 2024
On 2024-05-01 14:34, Felix Kuehling wrote:
>
>
> On 2024-04-30 19:29, Ramesh Errabolu wrote:
>> Analysis of code by Coverity, a static code analyser, has identified
>> a resource leak in the symbol hmm_range. This leak occurs when one of
>> the prior steps before it is released encounters an error.
>>
>> Signed-off-by: Ramesh Errabolu <Ramesh.Errabolu at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> index 386875e6eb96..dcb1d5d3f860 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
>> @@ -1658,7 +1658,7 @@ static int svm_range_validate_and_map(struct
>> mm_struct *mm,
>> start = map_start << PAGE_SHIFT;
>> end = (map_last + 1) << PAGE_SHIFT;
>> for (addr = start; !r && addr < end; ) {
>> - struct hmm_range *hmm_range;
>> + struct hmm_range *hmm_range = NULL;
>> unsigned long map_start_vma;
>> unsigned long map_last_vma;
>> struct vm_area_struct *vma;
>> @@ -1696,7 +1696,9 @@ static int svm_range_validate_and_map(struct
>> mm_struct *mm,
>> }
>> svm_range_lock(prange);
>> - if (!r && amdgpu_hmm_range_get_pages_done(hmm_range)) {
>> +
>> + // Free backing memory of hmm_range if it was initialized
>> + if (hmm_range && amdgpu_hmm_range_get_pages_done(hmm_range)) {
>> pr_debug("hmm update the range, need validate again\n");
>> r = -EAGAIN;
>
> Nack! This can now override other error codes that aren't meant to be
> overridden with -EAGAIN.
>
> I think a better solution would be to just revserse this condition to
> ensure that amdgpu_hmm_range_get_pages_done is always called:
>
> if (amdgpu_hmm_range_get_pages_done(hmm_range) && !r) {
Correction: You still need the NULL check:
if (hmm_range &&
amdgpu_hmm_range_get_pages_done(hmm_range) &&
!r) {
...
}
Regards,
Felix
> ...
> r = -EAGAIN;
> }
>
> Regards,
> Felix
>
>> }
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