Nouveau - Mar 2015 - [PATCH] instmem/gk20a: fix crash during error path

If a memory allocation fails when using the DMA allocator,
gk20a_instobj_dtor_dma() will be called on the failed instmem object.
At this time, node->handle might not be NULL despite the call to
dma_alloc_attrs() having failed. node->cpuaddr is the right member to
check for such a failure, so use it instead.

Reported-by: Vince Hsu <vinceh at nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 drm/nouveau/nvkm/subdev/instmem/gk20a.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drm/nouveau/nvkm/subdev/instmem/gk20a.c
b/drm/nouveau/nvkm/subdev/instmem/gk20a.c
index fcba72eb74a3..dd0994d9ebfc 100644
--- a/drm/nouveau/nvkm/subdev/instmem/gk20a.c
+++ b/drm/nouveau/nvkm/subdev/instmem/gk20a.c
@@ -148,7 +148,7 @@ gk20a_instobj_dtor_dma(struct gk20a_instobj_priv *_node)
 	struct gk20a_instmem_priv *priv = (void *)nvkm_instmem(node);
 	struct device *dev = nv_device_base(nv_device(priv));
 
-	if (unlikely(!node->handle))
+	if (unlikely(!node->cpuaddr))
 		return;
 
 	dma_free_attrs(dev, _node->mem->size << PAGE_SHIFT,
node->cpuaddr,
-- 
2.3.2

On Tue, Mar 10, 2015 at 03:46:08PM +0900, Alexandre Courbot
wrote:
> If a memory allocation fails when using the DMA allocator,
> gk20a_instobj_dtor_dma() will be called on the failed instmem object.
> At this time, node->handle might not be NULL despite the call to
> dma_alloc_attrs() having failed. node->cpuaddr is the right member to
> check for such a failure, so use it instead.
Indeed. The DMA address handle is in fact the very opposite of 0 in the
failure case (DMA_ERROR_CODE).

Reviewed-by: Thierry Reding <treding at nvidia.com>
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