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From:   Aditya Pakki <pakki001@umn.edu>
To:     pakki001@umn.edu
Cc:     kjlu@umn.edu, Jaehoon Chung <jh80.chung@samsung.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Kukjin Kim <kgene@kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mmc: dw_mmc: Fix to avoid potential NULL pointer dereference
Date:   Mon, 18 Mar 2019 19:19:18 -0500
Message-Id: <20190319001918.12042-1-pakki001@umn.edu>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

of_match_node can fail and return NULL in case no matching structure.
The patches checks for such a scenario and returns -ENXIO.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
---
 drivers/mmc/host/dw_mmc-exynos.c | 2 ++
 drivers/mmc/host/dw_mmc-k3.c     | 2 ++
 drivers/mmc/host/dw_mmc-pltfm.c  | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
index d46c3439b508..8a75d7314606 100644
--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/drivers/mmc/host/dw_mmc-exynos.c
@@ -554,6 +554,8 @@ static int dw_mci_exynos_probe(struct platform_device *pdev)
 	int ret;
 
 	match = of_match_node(dw_mci_exynos_match, pdev->dev.of_node);
+	if (!match)
+		return -ENXIO;
 	drv_data = match->data;
 
 	pm_runtime_get_noresume(&pdev->dev);
diff --git a/drivers/mmc/host/dw_mmc-k3.c b/drivers/mmc/host/dw_mmc-k3.c
index 89cdb3d533bb..cc50b7546a20 100644
--- a/drivers/mmc/host/dw_mmc-k3.c
+++ b/drivers/mmc/host/dw_mmc-k3.c
@@ -459,6 +459,8 @@ static int dw_mci_k3_probe(struct platform_device *pdev)
 	const struct of_device_id *match;
 
 	match = of_match_node(dw_mci_k3_match, pdev->dev.of_node);
+	if (!match)
+		return -ENXIO;
 	drv_data = match->data;
 
 	return dw_mci_pltfm_register(pdev, drv_data);
diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
index 58c13e21bd5a..b1948989f617 100644
--- a/drivers/mmc/host/dw_mmc-pltfm.c
+++ b/drivers/mmc/host/dw_mmc-pltfm.c
@@ -82,6 +82,8 @@ static int dw_mci_pltfm_probe(struct platform_device *pdev)
 
 	if (pdev->dev.of_node) {
 		match = of_match_node(dw_mci_pltfm_match, pdev->dev.of_node);
+		if (!match)
+			return -ENXIO;
 		drv_data = match->data;
 	}
 
-- 
2.17.1