drm/exynos: return NULL if exynos_pages_to_sg fails

exynos_pages_to_sg() internally calls sg_kmalloc() which can return
no pages when the system is under high memory crunch. One such instance
is chromeos-install in the chromeos. This patch adds check for the return
value of the function in subject to return NULL on failure.

Signed-off-by: Subash Patel <subash.ramaswamy@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
index 274909271c36..cb29e474da8e 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -86,6 +86,10 @@ static struct sg_table *
         npages = buf->size / buf->page_size;
 
         sgt = exynos_pages_to_sg(buf->pages, npages, buf->page_size);
+        if (!sgt) {
+                DRM_DEBUG_PRIME("exynos_pages_to_sg returned NULL!\n");
+                goto err_unlock;
+        }
         nents = dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
 
         DRM_DEBUG_PRIME("npages = %d buffer size = 0x%lx page_size = 0x%lx\n",