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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Prakash Kamliya <pkamliya@codeaurora.org>,
        Sharat Masetty <smasetty@codeaurora.org>,
        Rob Clark <robdclark@gmail.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.9 137/177] drm/msm: fix leak in failed get_pages
Date:   Fri, 23 Mar 2018 10:54:25 +0100
Message-Id: <20180323094211.262170268@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Prakash Kamliya <pkamliya@codeaurora.org>


[ Upstream commit 62e3a3e342af3c313ab38603811ecdb1fcc79edb ]

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@codeaurora.org>
Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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
@@ -91,14 +91,17 @@ 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:
 		 */
@@ -121,7 +124,10 @@ 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 (use_pages(obj))