gpu: nvgpu: Fixes in dupe free

gr_gk20a.c : railgating path the crash was seen
 with multiple frees happening
acr_gm20b.c : failure path, kernel panic was seen,
 with multiple frees

Change-Id: Ifc5e78c0ee74799c7f78e6030c02d1a27d545a1e
Signed-off-by: Supriya <ssharatkumar@nvidia.com>
Reviewed-on: http://git-master/r/494161
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
index 661a2ca3..69fe4901 100644
--- a/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/gr_gk20a.c
@@ -2269,7 +2269,10 @@ static void gk20a_gr_destroy_ctx_buffer(struct platform_device *pdev,
                                         struct gr_ctx_buffer_desc *desc)
 {
         struct device *dev = &pdev->dev;
-        gk20a_free_sgtable(&desc->sgt);
+        if (!desc)
+                return;
+        if (desc->sgt)
+                gk20a_free_sgtable(&desc->sgt);
         dma_free_attrs(dev, desc->size, desc->pages,
                        desc->iova, &desc->attrs);
 }