linux-kernel - [PATCH 4.4 21/44] drm/msm: Fix null pointer dereference on pointer edp

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Message-Id: <20211025190932.986053398@linuxfoundation.org>
Date:   Mon, 25 Oct 2021 21:14:02 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Colin Ian King <colin.king@...onical.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Rob Clark <robdclark@...omium.org>
Subject: [PATCH 4.4 21/44] drm/msm: Fix null pointer dereference on pointer edp

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

commit 2133c4fc8e1348dcb752f267a143fe2254613b34 upstream.

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@...onical.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Link: https://lore.kernel.org/r/20210929121857.213922-1-colin.king@canonical.com
Signed-off-by: Rob Clark <robdclark@...omium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/gpu/drm/msm/edp/edp_ctrl.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
+++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
@@ -1095,7 +1095,7 @@ void msm_edp_ctrl_power(struct edp_ctrl
 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) {
@@ -1103,6 +1103,7 @@ int msm_edp_ctrl_init(struct msm_edp *ed
 		return -EINVAL;
 	}
 
+	dev = &edp->pdev->dev;
 	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
 	if (!ctrl)
 		return -ENOMEM;