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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>,
	kernel-janitors@vger.kernel.org,
	Linus Walleij <linus.walleij@stericsson.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dma: imx-dma: fix signedness bug
Date: Wed, 20 Oct 2010 06:35:42 +0000	[thread overview]
Message-ID: <20101020063542.GD28242@pengutronix.de> (raw)
In-Reply-To: <AANLkTik15Z2_wyDRDOHOnpKKPgb+PHWs477esndgWmex@mail.gmail.com>

On Tue, Oct 19, 2010 at 03:26:05PM -0700, Dan Williams wrote:
> On Sun, Oct 17, 2010 at 7:51 AM, Vasiliy Kulikov <segooon@gmail.com> wrote:
> > mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
> > failed imx_dma_request_by_prio() made no sence.  Explicitly check
> > signed values.
> >
> > Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
> > ---
> >  drivers/dma/imx-dma.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> > index 346be62..75d870f 100644
> > --- a/drivers/dma/imx-dma.c
> > +++ b/drivers/dma/imx-dma.c
> > @@ -335,7 +335,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
> >
> >                imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
> >                                DMA_PRIO_MEDIUM);
> > -               if (imxdmac->channel < 0)
> > +               if ((int)imxdmac->channel < 0)
> >                        goto err_init;
> 
> Should this be:
> 
>                if ((int)imxdmac->channel < 0) {
>                        ret = -ENODEV;
>                        goto err_init;
>                }
> 
> ...because I get the following in my compilation tests.

Yes, ret is clearly used uninitialized. I wonder why my gcc-4.3.2 compiler
does not warn me about this :(

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
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WARNING: multiple messages have this Message-ID (diff)
From: Sascha Hauer <s.hauer@pengutronix.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>,
	kernel-janitors@vger.kernel.org,
	Linus Walleij <linus.walleij@stericsson.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dma: imx-dma: fix signedness bug
Date: Wed, 20 Oct 2010 08:35:42 +0200	[thread overview]
Message-ID: <20101020063542.GD28242@pengutronix.de> (raw)
In-Reply-To: <AANLkTik15Z2_wyDRDOHOnpKKPgb+PHWs477esndgWmex@mail.gmail.com>

On Tue, Oct 19, 2010 at 03:26:05PM -0700, Dan Williams wrote:
> On Sun, Oct 17, 2010 at 7:51 AM, Vasiliy Kulikov <segooon@gmail.com> wrote:
> > mxdmac->channel was unsigned, so check (imxdmac->channel < 0) for
> > failed imx_dma_request_by_prio() made no sence.  Explicitly check
> > signed values.
> >
> > Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
> > ---
> >  drivers/dma/imx-dma.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
> > index 346be62..75d870f 100644
> > --- a/drivers/dma/imx-dma.c
> > +++ b/drivers/dma/imx-dma.c
> > @@ -335,7 +335,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
> >
> >                imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
> >                                DMA_PRIO_MEDIUM);
> > -               if (imxdmac->channel < 0)
> > +               if ((int)imxdmac->channel < 0)
> >                        goto err_init;
> 
> Should this be:
> 
>                if ((int)imxdmac->channel < 0) {
>                        ret = -ENODEV;
>                        goto err_init;
>                }
> 
> ...because I get the following in my compilation tests.

Yes, ret is clearly used uninitialized. I wonder why my gcc-4.3.2 compiler
does not warn me about this :(

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

  reply	other threads:[~2010-10-20  6:35 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-17 14:51 [PATCH] dma: imx-dma: fix signedness bug Vasiliy Kulikov
2010-10-17 14:51 ` Vasiliy Kulikov
2010-10-18  8:02 ` Sascha Hauer
2010-10-18  8:02   ` Sascha Hauer
2010-10-19 22:26 ` Dan Williams
2010-10-19 22:26   ` Dan Williams
2010-10-20  6:35   ` Sascha Hauer [this message]
2010-10-20  6:35     ` Sascha Hauer
2010-10-20  6:37   ` Sascha Hauer
2010-10-20  6:37     ` Sascha Hauer

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