mtd: rawnand: atmel: fix possible object reference leak

BugLink: https://bugs.launchpad.net/bugs/1855787
commit a12085d13997ed15f745f33a0e01002541160179 upstream.

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: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
Suggested-by: Boris Brezillon <bbrezillon@kernel.org>
Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/mtd/nand/atmel/pmecc.c b/drivers/mtd/nand/atmel/pmecc.c
index ca0a70389ba95521e6cd140c1fcc676413d8a651..ad44b80c524f2dcbb5fbf519da94a0881989d90f 100644 (file)
--- a/drivers/mtd/nand/atmel/pmecc.c
+++ b/drivers/mtd/nand/atmel/pmecc.c
@@ -876,23 +876,32 @@ static struct atmel_pmecc *atmel_pmecc_get_by_node(struct device *userdev,
 {
        struct platform_device *pdev;
        struct atmel_pmecc *pmecc, **ptr;
+       int ret;
 
        pdev = of_find_device_by_node(np);
-       if (!pdev || !platform_get_drvdata(pdev))
+       if (!pdev)
                return ERR_PTR(-EPROBE_DEFER);
+       pmecc = platform_get_drvdata(pdev);
+       if (!pmecc) {
+               ret = -EPROBE_DEFER;
+               goto err_put_device;
+       }
 
        ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
-       if (!ptr)
-               return ERR_PTR(-ENOMEM);
-
-       get_device(&pdev->dev);
-       pmecc = platform_get_drvdata(pdev);
+       if (!ptr) {
+               ret = -ENOMEM;
+               goto err_put_device;
+       }
 
        *ptr = pmecc;
 
        devres_add(userdev, ptr);
 
        return pmecc;
+
+err_put_device:
+       put_device(&pdev->dev);
+       return ERR_PTR(ret);
 }
 
 static const int atmel_pmecc_strengths[] = { 2, 4, 8, 12, 24, 32 };