Re: [PATCH v2] drm/amdgpu: Use kmalloc_array() instead of kmalloc()

Kuehling, Felix Mon, 22 Sep 2025 06:59:53 -0700

On 2025-09-18 03:12, Rahul Kumar wrote:

Documentation/process/deprecated.rst recommends against the use of
kmalloc with dynamic size calculations due to the risk of overflow and
smaller allocation being made than the caller was expecting.


Replace kmalloc() with kmalloc_array() in amdgpu_amdkfd_gfx_v10.c,
amdgpu_amdkfd_gfx_v10_3.c, amdgpu_amdkfd_gfx_v11.c and
amdgpu_amdkfd_gfx_v12.c to make the intended allocation size clearer
and avoid potential overflow issues.

Suggested-by: Felix Kuehling <felix.kuehl...@amd.com>
Signed-off-by: Rahul Kumar <rk0006...@gmail.com>


Thank you. I applied the patch to amd-staging-drm-next.

Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>

---
Changes since v1:
- Extend fix to amdgpu_amdkfd_gfx_v10_3.c, amdgpu_amdkfd_gfx_v11.c and
   amdgpu_amdkfd_gfx_v12.c as suggested.
- Added Suggested-by tag.
Link to v1:
https://lore.kernel.org/all/f782159b-ad3f-4d0c-8476-50a701bf2...@amd.com/
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c   | 4 ++--
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10_3.c | 4 ++--
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v11.c   | 4 ++--
  drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v12.c   | 4 ++--
  4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c
index 04ef0ca10541..0239114fb6c4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10.c
@@ -352,7 +352,7 @@ static int kgd_hqd_dump(struct amdgpu_device *adev,
                (*dump)[i++][1] = RREG32_SOC15_IP(GC, addr);            \
        } while (0)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

@@ -449,7 +449,7 @@ static int kgd_hqd_sdma_dump(struct amdgpu_device *adev,

  #undef HQD_N_REGS
  #define HQD_N_REGS (19+6+7+10)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10_3.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10_3.c

index 6d08bc2781a3..f2278a0937ff 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10_3.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v10_3.c
@@ -338,7 +338,7 @@ static int hqd_dump_v10_3(struct amdgpu_device *adev,
                (*dump)[i++][1] = RREG32_SOC15_IP(GC, addr);            \
        } while (0)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

@@ -435,7 +435,7 @@ static int hqd_sdma_dump_v10_3(struct amdgpu_device *adev,

  #undef HQD_N_REGS
  #define HQD_N_REGS (19+6+7+12)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v11.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v11.c

index e0e6a6a49d90..aaccf0b9947d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v11.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v11.c
@@ -323,7 +323,7 @@ static int hqd_dump_v11(struct amdgpu_device *adev,
                (*dump)[i++][1] = RREG32(addr);         \
        } while (0)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

@@ -420,7 +420,7 @@ static int hqd_sdma_dump_v11(struct amdgpu_device *adev,

  #undef HQD_N_REGS
  #define HQD_N_REGS (7+11+1+12+12)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v12.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v12.c

index 6f0dc23c901b..e0ceab400b2d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v12.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v12.c
@@ -115,7 +115,7 @@ static int hqd_dump_v12(struct amdgpu_device *adev,
                (*dump)[i++][1] = RREG32(addr);         \
        } while (0)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

@@ -146,7 +146,7 @@ static int hqd_sdma_dump_v12(struct amdgpu_device *adev,

  #undef HQD_N_REGS
  #define HQD_N_REGS (last_reg - first_reg + 1)

- *dump = kmalloc(HQD_N_REGS*2*sizeof(uint32_t), GFP_KERNEL);

+       *dump = kmalloc_array(HQD_N_REGS, sizeof(**dump), GFP_KERNEL);
        if (*dump == NULL)
                return -ENOMEM;

Re: [PATCH v2] drm/amdgpu: Use kmalloc_array() instead of kmalloc()

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