[PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Ramesh Errabolu]

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@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;
 		}
-- 
2.34.1

Re: [PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Philip Yang]

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Re: [PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Felix Kuehling]

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@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) {
			...
			r = -EAGAIN;
		}

Regards,
   Felix

>   		}

Re: [PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Felix Kuehling]

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@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
> 
>>           }

RE: [PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()

[Errabolu, Ramesh]

[AMD Official Use Only - General]

Good catch on dropping return values

Regards,
Ramesh

-----Original Message-----
From: Kuehling, Felix <Felix.Kuehling@amd.com>
Sent: Thursday, May 2, 2024 12:30 AM
To: Errabolu, Ramesh <Ramesh.Errabolu@amd.com>; amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/amd/amdkfd: Fix a resource leak in svm_range_validate_and_map()


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@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
>
>>           }