From: Thomas Zimmermann Date: Tue, 15 Jul 2025 08:26:22 +0000 (+0200) Subject: Revert "drm/amdgpu: Use dma_buf from GEM object instance" X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=3eb61d7cb74cea2ea697363669fa256937164758;p=users%2Fjedix%2Flinux-maple.git Revert "drm/amdgpu: Use dma_buf from GEM object instance" This reverts commit 515986100d176663d0a03219a3056e4252f729e6. The dma_buf field in struct drm_gem_object is not stable over the object instance's lifetime. The field becomes NULL when user space releases the final GEM handle on the buffer object. This resulted in a NULL-pointer deref. Workarounds in commit 5307dce878d4 ("drm/gem: Acquire references on GEM handles for framebuffers") and commit f6bfc9afc751 ("drm/framebuffer: Acquire internal references on GEM handles") only solved the problem partially. They especially don't work for buffer objects without a DRM framebuffer associated. Hence, this revert to going back to using .import_attach->dmabuf. Signed-off-by: Thomas Zimmermann Reviewed-by: Simona Vetter Acked-by: Alex Deucher Link: https://lore.kernel.org/r/20250715082635.34974-1-tzimmermann@suse.de --- diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c index ff98c87b2e0b..5743ebb2f1b7 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c @@ -514,7 +514,7 @@ bool amdgpu_dmabuf_is_xgmi_accessible(struct amdgpu_device *adev, return false; if (drm_gem_is_imported(obj)) { - struct dma_buf *dma_buf = obj->dma_buf; + struct dma_buf *dma_buf = obj->import_attach->dmabuf; if (dma_buf->ops != &amdgpu_dmabuf_ops) /* No XGMI with non AMD GPUs */ diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c index 6626a6e64ff5..d1ccbfcf21fa 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c @@ -317,7 +317,8 @@ static int amdgpu_gem_object_open(struct drm_gem_object *obj, */ if (!vm->is_compute_context || !vm->process_info) return 0; - if (!drm_gem_is_imported(obj) || !dma_buf_is_dynamic(obj->dma_buf)) + if (!drm_gem_is_imported(obj) || + !dma_buf_is_dynamic(obj->import_attach->dmabuf)) return 0; mutex_lock_nested(&vm->process_info->lock, 1); if (!WARN_ON(!vm->process_info->eviction_fence)) { diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 5cacf5717016..8777ed8facd6 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -1276,7 +1276,7 @@ int amdgpu_vm_bo_update(struct amdgpu_device *adev, struct amdgpu_bo_va *bo_va, struct drm_gem_object *obj = &bo->tbo.base; if (drm_gem_is_imported(obj) && bo_va->is_xgmi) { - struct dma_buf *dma_buf = obj->dma_buf; + struct dma_buf *dma_buf = obj->import_attach->dmabuf; struct drm_gem_object *gobj = dma_buf->priv; struct amdgpu_bo *abo = gem_to_amdgpu_bo(gobj);