[PATCH 3.16 175/366] drm/msm: fix leak in failed get_pages

[Ben Hutchings]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Prakash Kamliya <pkamliya@xxxxxxxxxxxxxx>

commit 62e3a3e342af3c313ab38603811ecdb1fcc79edb upstream.

get_pages doesn't keep a reference of the pages allocated
when it fails later in the code path. This can lead to
a memory leak. Keep reference of the allocated pages so
that it can be freed when msm_gem_free_object gets called
later during cleanup.

Signed-off-by: Prakash Kamliya <pkamliya@xxxxxxxxxxxxxx>
Signed-off-by: Sharat Masetty <smasetty@xxxxxxxxxxxxxx>
Signed-off-by: Rob Clark <robdclark@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/msm_gem.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -83,14 +83,17 @@ static struct page **get_pages(struct dr
 			return p;
 		}
 
+		msm_obj->pages = p;
+
 		msm_obj->sgt = drm_prime_pages_to_sg(p, npages);
 		if (IS_ERR(msm_obj->sgt)) {
+			void *ptr = ERR_CAST(msm_obj->sgt);
+
 			dev_err(dev->dev, "failed to allocate sgt\n");
-			return ERR_CAST(msm_obj->sgt);
+			msm_obj->sgt = NULL;
+			return ptr;
 		}
 
-		msm_obj->pages = p;
-
 		/* For non-cached buffers, ensure the new pages are clean
 		 * because display controller, GPU, etc. are not coherent:
 		 */
@@ -113,7 +116,10 @@ static void put_pages(struct drm_gem_obj
 		if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
 			dma_unmap_sg(obj->dev->dev, msm_obj->sgt->sgl,
 					msm_obj->sgt->nents, DMA_BIDIRECTIONAL);
-		sg_free_table(msm_obj->sgt);
+
+		if (msm_obj->sgt)
+			sg_free_table(msm_obj->sgt);
+
 		kfree(msm_obj->sgt);
 
 		if (iommu_present(&platform_bus_type))