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From:   Nicolas Boichat <drinkcat@chromium.org>
To:     Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     Nicolas Boichat <drinkcat@chromium.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Pi-Hsun Shih <pihsun@chromium.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org,
        linux-remoteproc@vger.kernel.org
Subject: [PATCH v2] rpmsg: Avoid double-free in mtk_rpmsg_register_device
Date:   Wed,  2 Sep 2020 19:07:15 +0800
Message-Id: <20200902190709.v2.1.I56cf27cd59f4013bd074dc622c8b8248b034a4cc@changeid>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

If rpmsg_register_device fails, it will call
mtk_rpmsg_release_device which already frees mdev.

Fixes: 7017996951fde84 ("rpmsg: add rpmsg support for mt8183 SCP.")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
---

Changes in v2:
 - Drop useless if and ret variable (Markus Elfring)

 drivers/rpmsg/mtk_rpmsg.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/rpmsg/mtk_rpmsg.c b/drivers/rpmsg/mtk_rpmsg.c
index 83f2b8804ee989d..96a17ec2914011d 100644
--- a/drivers/rpmsg/mtk_rpmsg.c
+++ b/drivers/rpmsg/mtk_rpmsg.c
@@ -200,7 +200,6 @@ static int mtk_rpmsg_register_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
 	struct rpmsg_device *rpdev;
 	struct mtk_rpmsg_device *mdev;
 	struct platform_device *pdev = mtk_subdev->pdev;
-	int ret;
 
 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
 	if (!mdev)
@@ -219,13 +218,7 @@ static int mtk_rpmsg_register_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
 	rpdev->dev.parent = &pdev->dev;
 	rpdev->dev.release = mtk_rpmsg_release_device;
 
-	ret = rpmsg_register_device(rpdev);
-	if (ret) {
-		kfree(mdev);
-		return ret;
-	}
-
-	return 0;
+	return rpmsg_register_device(rpdev);
 }
 
 static void mtk_register_device_work_function(struct work_struct *register_work)
-- 
2.28.0.402.g5ffc5be6b7-goog