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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,
        =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= <jose.exposito89@gmail.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Subject: [PATCH 5.15 098/171] drm/msm/dsi: invalid parameter check in msm_dsi_phy_enable
Date:   Mon, 31 Jan 2022 11:56:03 +0100
Message-Id: <20220131105233.355835390@linuxfoundation.org>
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From: José Expósito <jose.exposito89@gmail.com>

commit 5e761a2287234bc402ba7ef07129f5103bcd775c upstream.

The function performs a check on the "phy" input parameter, however, it
is used before the check.

Initialize the "dev" variable after the sanity check to avoid a possible
NULL pointer dereference.

Fixes: 5c8290284402b ("drm/msm/dsi: Split PHY drivers to separate files")
Addresses-Coverity-ID: 1493860 ("Null pointer dereference")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220116181844.7400-1-jose.exposito89@gmail.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/msm/dsi/phy/dsi_phy.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
+++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
@@ -806,12 +806,14 @@ int msm_dsi_phy_enable(struct msm_dsi_ph
 			struct msm_dsi_phy_clk_request *clk_req,
 			struct msm_dsi_phy_shared_timings *shared_timings)
 {
-	struct device *dev = &phy->pdev->dev;
+	struct device *dev;
 	int ret;
 
 	if (!phy || !phy->cfg->ops.enable)
 		return -EINVAL;
 
+	dev = &phy->pdev->dev;
+
 	ret = dsi_phy_enable_resource(phy);
 	if (ret) {
 		DRM_DEV_ERROR(dev, "%s: resource enable failed, %d\n",