linux-kernel - [PATCH v2] gpu: ipu-v3: fix a possible NULL dereference

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Message-Id: <1472026637-12052-1-git-send-email-clabbe.montjoie@gmail.com>
Date:   Wed, 24 Aug 2016 10:17:17 +0200
From:   LABBE Corentin <clabbe.montjoie@...il.com>
To:     p.zabel@...gutronix.de
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        LABBE Corentin <clabbe.montjoie@...il.com>
Subject: [PATCH v2] gpu: ipu-v3: fix a possible NULL dereference

of_match_device could return NULL, and so cause a NULL pointer
dereference later.

For fixing this problem, we use of_device_get_match_data(), this will
simplify the code a little by using a standard function for
getting the match data.

Testing the return value of of_device_get_match_data is also necessary
for avoiding a second NULL deref later on devtype.

Signed-off-by: LABBE Corentin <clabbe.montjoie@...il.com>
---
Changes in v2:
 - Add a test on devtype for avoiding a second NULL deref.

 drivers/gpu/ipu-v3/ipu-common.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/ipu-v3/ipu-common.c b/drivers/gpu/ipu-v3/ipu-common.c
index 99dcacf..8072470 100644
--- a/drivers/gpu/ipu-v3/ipu-common.c
+++ b/drivers/gpu/ipu-v3/ipu-common.c
@@ -1207,15 +1207,15 @@ EXPORT_SYMBOL_GPL(ipu_dump);
 
 static int ipu_probe(struct platform_device *pdev)
 {
-	const struct of_device_id *of_id =
-			of_match_device(imx_ipu_dt_ids, &pdev->dev);
 	struct ipu_soc *ipu;
 	struct resource *res;
 	unsigned long ipu_base;
 	int i, ret, irq_sync, irq_err;
 	const struct ipu_devtype *devtype;
 
-	devtype = of_id->data;
+	devtype = of_device_get_match_data(&pdev->dev);
+	if (!devtype)
+		return -EINVAL;
 
 	irq_sync = platform_get_irq(pdev, 0);
 	irq_err = platform_get_irq(pdev, 1);
-- 
2.7.3