[PATCH] drm/msm: Fix null pointer dereference on pointer edp

From: Colin King <colin.king@canonical.com>
To: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Dave Airlie <airlied@redhat.com>, Lyude Paul <lyude@redhat.com>,
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] drm/msm: Fix null pointer dereference on pointer edp
Date: Wed, 29 Sep 2021 13:18:57 +0100	[thread overview]
Message-ID: <20210929121857.213922-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The initialization of pointer dev dereferences pointer edp before
edp is null checked, so there is a potential null pointer deference
issue. Fix this by only dereferencing edp after edp has been null
checked.

Addresses-Coverity: ("Dereference before null check")
Fixes: ab5b0107ccf3 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/gpu/drm/msm/edp/edp_ctrl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c
index 4fb397ee7c84..fe1366b4c49f 100644
--- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
+++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
@@ -1116,7 +1116,7 @@ void msm_edp_ctrl_power(struct edp_ctrl *ctrl, bool on)
 int msm_edp_ctrl_init(struct msm_edp *edp)
 {
 	struct edp_ctrl *ctrl = NULL;
-	struct device *dev = &edp->pdev->dev;
+	struct device *dev;
 	int ret;
 
 	if (!edp) {
@@ -1124,6 +1124,7 @@ int msm_edp_ctrl_init(struct msm_edp *edp)
 		return -EINVAL;
 	}
 
+	dev = &edp->pdev->dev;
 	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
 	if (!ctrl)
 		return -ENOMEM;
-- 
2.32.0

