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Message-ID: <20190205201158.3cbcc628@xps13>
Date: Tue, 5 Feb 2019 20:11:58 +0100
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: Wen Yang <yellowriver2010@...mail.com>
Cc: "tudor.ambarus@...rochip.com" <tudor.ambarus@...rochip.com>,
"bbrezillon@...nel.org" <bbrezillon@...nel.org>,
"richard@....at" <richard@....at>,
"dwmw2@...radead.org" <dwmw2@...radead.org>,
"computersforpeace@...il.com" <computersforpeace@...il.com>,
"marek.vasut@...il.com" <marek.vasut@...il.com>,
"nicolas.ferre@...rochip.com" <nicolas.ferre@...rochip.com>,
"alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>,
"ludovic.desroches@...rochip.com" <ludovic.desroches@...rochip.com>,
"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] mtd: rawnand: atmel: fix possible object reference
leak
Hi Wen,
For the next version can you please post a series with the three
commits which are fixing the same reference leak? No need to add a
cover letter though.
Wen Yang <yellowriver2010@...mail.com> wrote on Tue, 5 Feb 2019
14:32:41 +0000:
> 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@...mail.com>
> Suggested-by: Boris Brezillon <bbrezillon@...nel.org>
> Reviewed-by: Boris Brezillon <bbrezillon@...nel.org>
> Reviewed-by: Miquel Raynal <miquel.raynal@...tlin.com>
> Acked-by: Miquel Raynal <miquel.raynal@...tlin.com>
> Cc: Tudor Ambarus <tudor.ambarus@...rochip.com>
> Cc: Boris Brezillon <bbrezillon@...nel.org>
> Cc: Miquel Raynal <miquel.raynal@...tlin.com>
> Cc: Richard Weinberger <richard@....at>
> Cc: David Woodhouse <dwmw2@...radead.org>
> Cc: Brian Norris <computersforpeace@...il.com>
> Cc: Marek Vasut <marek.vasut@...il.com>
> Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>
> Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>
> Cc: Ludovic Desroches <ludovic.desroches@...rochip.com>
> Cc: linux-mtd@...ts.infradead.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-kernel@...r.kernel.org
> ---
> drivers/mtd/nand/raw/atmel/pmecc.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
> index 555a74e..1477368 100644
> --- a/drivers/mtd/nand/raw/atmel/pmecc.c
> +++ b/drivers/mtd/nand/raw/atmel/pmecc.c
> @@ -876,16 +876,22 @@ 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);
> + if (!platform_get_drvdata(pdev)) {
> + ret = -EPROBE_DEFER;
> + goto err_put_device;
> + }
>
> ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
> - if (!ptr)
> - return ERR_PTR(-ENOMEM);
> + if (!ptr) {
> + ret = -ENOMEM;
> + goto err_put_device;
> + }
>
> - get_device(&pdev->dev);
> pmecc = platform_get_drvdata(pdev);
I just realized in the three cases, a first call
to platform_get_drvdata() is done to check if the returned pointer is
valid, and then a second one is done to actually retrieve the pointer.
Please avoid this repetition.
Thanks,
Miquèl
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