[PATCH v4 2/3] mtd: rawnand: jz4780: fix possible object reference leak

From: Wen Yang <yellowriver2010@hotmail.com>
To: "bbrezillon@kernel.org" <bbrezillon@kernel.org>,
	"miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
	"tudor.ambarus@microchip.com" <tudor.ambarus@microchip.com>,
	"richard@nod.at" <richard@nod.at>,
	"dwmw2@infradead.org" <dwmw2@infradead.org>,
	"computersforpeace@gmail.com" <computersforpeace@gmail.com>,
	"marek.vasut@gmail.com" <marek.vasut@gmail.com>
Cc: "alexandre.belloni@bootlin.com" <alexandre.belloni@bootlin.com>,
	Wen Yang <yellowriver2010@hotmail.com>,
	"nicolas.ferre@microchip.com" <nicolas.ferre@microchip.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"ludovic.desroches@microchip.com"
	<ludovic.desroches@microchip.com>,
	"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: [PATCH v4 2/3] mtd: rawnand: jz4780: fix possible object reference leak
Date: Thu, 7 Feb 2019 12:02:45 +0000	[thread overview]
Message-ID: <HK0PR02MB363417B2E91D8D6D7D31B1D6B2680@HK0PR02MB3634.apcprd02.prod.outlook.com> (raw)

of_find_device_by_node() takes a reference to the struct device
when it finds a match via get_device, there is no need to call
get_device() twice.
We also should make sure to drop the reference to the device
taken by of_find_device_by_node() on driver unbind.

Fixes: ae02ab00aa3c ("mtd: nand: jz4780: driver for NAND devices on JZ4780 SoCs")
Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
---
v4->v3: Add people in Cc and remove all lines.
v3->v2: Avoid two times of calling grtform_get_drvdata()
v2->v1: Since there is the only one user, let's remove the err_put_device label.

 drivers/mtd/nand/raw/jz4780_bch.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/raw/jz4780_bch.c b/drivers/mtd/nand/raw/jz4780_bch.c
index 7201827..7aab851 100644
--- a/drivers/mtd/nand/raw/jz4780_bch.c
+++ b/drivers/mtd/nand/raw/jz4780_bch.c
@@ -281,12 +281,14 @@ static struct jz4780_bch *jz4780_bch_get(struct device_node *np)
 	struct jz4780_bch *bch;
 
 	pdev = of_find_device_by_node(np);
-	if (!pdev || !platform_get_drvdata(pdev))
+	if (!pdev)
 		return ERR_PTR(-EPROBE_DEFER);
-
-	get_device(&pdev->dev);
-
 	bch = platform_get_drvdata(pdev);
+	if (!bch) {
+		put_device(&pdev->dev);
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
 	clk_prepare_enable(bch->clk);
 
 	return bch;
-- 
2.7.4


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
