Re: [PATCH 4/5] drm/amdgpu: Fix null pointer dereference to bo

[Christian König]

Am 13.05.24 um 10:56 schrieb Ma Jun:

Check bo before using it

Signed-off-by: Ma Jun <jun....@amd.com>

Reviewed-by: Christian König <christian.koe...@amd.com>

---
  drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c | 16 +++++++++++-----
  1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c 
b/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
index 2b7b67916c1d..8269fd6828bf 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v12_0.c
@@ -497,9 +497,8 @@ static void gmc_v12_0_get_vm_pte(struct amdgpu_device *adev,
                                 uint64_t *flags)
  {
        struct amdgpu_bo *bo = mapping->bo_va->base.bo;
-       struct amdgpu_device *bo_adev = amdgpu_ttm_adev(bo->tbo.bdev);
-       bool coherent = bo->flags & AMDGPU_GEM_CREATE_COHERENT;
-       bool is_system = bo->tbo.resource->mem_type == TTM_PL_SYSTEM;
+       struct amdgpu_device *bo_adev;
+       bool coherent, is_system;

*flags &= ~AMDGPU_PTE_EXECUTABLE;

@@ -515,13 +514,20 @@ static void gmc_v12_0_get_vm_pte(struct amdgpu_device 
*adev,
                *flags &= ~AMDGPU_PTE_VALID;
        }

- if (bo && bo->flags & (AMDGPU_GEM_CREATE_COHERENT |

+       if (!bo)
+               return;
+
+       if (bo->flags & (AMDGPU_GEM_CREATE_COHERENT |
                               AMDGPU_GEM_CREATE_UNCACHED))
                *flags = (*flags & ~AMDGPU_PTE_MTYPE_GFX12_MASK) |
                         AMDGPU_PTE_MTYPE_GFX12(MTYPE_UC);

+ bo_adev = amdgpu_ttm_adev(bo->tbo.bdev);

+       coherent = bo->flags & AMDGPU_GEM_CREATE_COHERENT;
+       is_system = bo->tbo.resource->mem_type == TTM_PL_SYSTEM;
+
        /* WA for HW bug */
-       if ((bo && is_system) || ((bo_adev != adev) && coherent))
+       if (is_system || ((bo_adev != adev) && coherent))
                *flags |= AMDGPU_PTE_MTYPE_GFX12(MTYPE_NC);

}