[PATCH AUTOSEL 6.1 13/14] drm/amdgpu: fix dereference null return value for the function amdgpu_vm_pt_parent

[PATCH AUTOSEL 6.1 13/14] drm/amdgpu: fix dereference null return value for the function amdgpu_vm_pt_parent

[Sasha Levin]

From: Jesse Zhang <jesse.zhang@amd.com>

[ Upstream commit a0cf36546cc24ae1c95d72253c7795d4d2fc77aa ]

The pointer parent may be NULLed by the function amdgpu_vm_pt_parent.
To make the code more robust, check the pointer parent.

Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
index 69b3829bbe53f..370d02bdde862 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
@@ -754,11 +754,15 @@ int amdgpu_vm_pde_update(struct amdgpu_vm_update_params *params,
 			 struct amdgpu_vm_bo_base *entry)
 {
 	struct amdgpu_vm_bo_base *parent = amdgpu_vm_pt_parent(entry);
-	struct amdgpu_bo *bo = parent->bo, *pbo;
+	struct amdgpu_bo *bo, *pbo;
 	struct amdgpu_vm *vm = params->vm;
 	uint64_t pde, pt, flags;
 	unsigned int level;
 
+	if (WARN_ON(!parent))
+		return -EINVAL;
+
+	bo = parent->bo;
 	for (level = 0, pbo = bo->parent; pbo; ++level)
 		pbo = pbo->parent;
 
-- 
2.43.0

Re: [PATCH AUTOSEL 6.1 13/14] drm/amdgpu: fix dereference null return value for the function amdgpu_vm_pt_parent

[Pavel Machek]

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Hi!

> [ Upstream commit a0cf36546cc24ae1c95d72253c7795d4d2fc77aa ]
> 
> The pointer parent may be NULLed by the function amdgpu_vm_pt_parent.
> To make the code more robust, check the pointer parent.

If this can happen, it should not WARN().

If this can not happen, we don't need the patch in stable.

Best regards,
							Pavel
							
-- 
DENX Software Engineering GmbH,        Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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Re: [PATCH AUTOSEL 6.1 13/14] drm/amdgpu: fix dereference null return value for the function amdgpu_vm_pt_parent

[Christian König]

Am 18.06.24 um 11:11 schrieb Pavel Machek:
> Hi!
>
>> [ Upstream commit a0cf36546cc24ae1c95d72253c7795d4d2fc77aa ]
>>
>> The pointer parent may be NULLed by the function amdgpu_vm_pt_parent.
>> To make the code more robust, check the pointer parent.
> If this can happen, it should not WARN().
>
> If this can not happen, we don't need the patch in stable.

Right, that patch shouldn't be backported in any way.

Regards,
Christian.

>
> Best regards,
> 							Pavel
> 							

Re: [PATCH AUTOSEL 6.1 13/14] drm/amdgpu: fix dereference null return value for the function amdgpu_vm_pt_parent

[Sasha Levin]

On Tue, Jun 18, 2024 at 01:42:56PM +0200, Christian König wrote:
>Am 18.06.24 um 11:11 schrieb Pavel Machek:
>>Hi!
>>
>>>[ Upstream commit a0cf36546cc24ae1c95d72253c7795d4d2fc77aa ]
>>>
>>>The pointer parent may be NULLed by the function amdgpu_vm_pt_parent.
>>>To make the code more robust, check the pointer parent.
>>If this can happen, it should not WARN().
>>
>>If this can not happen, we don't need the patch in stable.
>
>Right, that patch shouldn't be backported in any way.

I'll drop it, thanks!

-- 
Thanks,
Sasha