Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 2 Feb 2018 06:42:33 -0600
From:   "Gustavo A. R. Silva" <garsilva@embeddedor.com>
To:     Lloyd Atkinson <latkinso@codeaurora.org>,
        Rob Clark <robdclark@gmail.com>,
        David Airlie <airlied@linux.ie>
Cc:     linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        "Gustavo A. R. Silva" <garsilva@embeddedor.com>
Subject: [PATCH] drm/msm/dsi: Fix potential NULL pointer dereference in
 msm_dsi_modeset_init
Message-ID: <20180202124233.GA5056@embeddedor.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

_dev_ is being dereferenced before it is null checked, hence there
is a potential null pointer dereference.

Fix this by moving the pointer dereference after _dev_ has been
null checked.

Fixes: d4e7f38d70ef ("drm/msm/dsi: check msm_dsi and dsi pointers before use")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/gpu/drm/msm/dsi/dsi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index ee7e090..b744bcc 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -192,13 +192,14 @@ void __exit msm_dsi_unregister(void)
 int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
 			 struct drm_encoder *encoder)
 {
-	struct msm_drm_private *priv = dev->dev_private;
+	struct msm_drm_private *priv;
 	struct drm_bridge *ext_bridge;
 	int ret;
 
 	if (WARN_ON(!encoder) || WARN_ON(!msm_dsi) || WARN_ON(!dev))
 		return -EINVAL;
 
+	priv = dev->dev_private;
 	msm_dsi->dev = dev;
 
 	ret = msm_dsi_host_modeset_init(msm_dsi->host, dev);
-- 
2.7.4