[PATCH 3/3] drm/tegra: gem: Check before freeing CMA memory

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

dma_free_writecombine() must not be called on a buffer that couldn't be
allocated. Check for a valid virtual address before attempting to free
the memory to avoid a crash.

Reported-by: Sean Paul <seanpaul at google.com>
Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 drivers/gpu/drm/tegra/gem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 4a4f967c6397..da32086cbeaf 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -210,7 +210,7 @@ static void tegra_bo_free(struct drm_device *drm, struct tegra_bo *bo)
 		drm_gem_put_pages(&bo->gem, bo->pages, true, true);
 		sg_free_table(bo->sgt);
 		kfree(bo->sgt);
-	} else {
+	} else if (bo->vaddr) {
 		dma_free_writecombine(drm->dev, bo->gem.size, bo->vaddr,
 				      bo->paddr);
 	}
-- 
2.1.3