linux-kernel - Re: [PATCH] i2c: tegra: fix a possible NULL dereference

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Message-ID: <20151112135549.GB1131@ulmo>
Date:	Thu, 12 Nov 2015 14:55:49 +0100
From:	Thierry Reding <thierry.reding@...il.com>
To:	Jon Hunter <jonathanh@...dia.com>
Cc:	LABBE Corentin <clabbe.montjoie@...il.com>, gnurou@...il.com,
	ldewangan@...dia.com, swarren@...dotorg.org, wsa@...-dreams.de,
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-tegra@...r.kernel.org
Subject: Re: [PATCH] i2c: tegra: fix a possible NULL dereference

On Thu, Nov 12, 2015 at 01:40:56PM +0000, Jon Hunter wrote:
> 
> On 12/11/15 12:29, Thierry Reding wrote:
> > * PGP Signed by an unknown key
> > 
> > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote:
> >> of_match_device could return NULL, and so cause a NULL pointer
> > 
> > No. There is no way that of_match_device() can ever fail. The driver
> > core uses the same table to match the OF device to the driver, so the
> > only case where of_match_device() would return NULL is if no match was
> > found, in which case the tegra_i2c_probe() function would never have
> > been called in the first place.
> 
> Right and so ...
> 
> >> dereference later at line 809:
> >> i2c_dev->hw = match->data;
> >>
> >> Signed-off-by: LABBE Corentin <clabbe.montjoie@...il.com>
> >> ---
> >>  drivers/i2c/busses/i2c-tegra.c | 3 +++
> >>  1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> >> index a0522fc..c803551 100644
> >> --- a/drivers/i2c/busses/i2c-tegra.c
> >> +++ b/drivers/i2c/busses/i2c-tegra.c
> >> @@ -806,7 +806,10 @@ static int tegra_i2c_probe(struct platform_device *pdev)
> >>  
> >>  	if (pdev->dev.of_node) {
> 
> Can we get rid of this if-statement?

Yeah, I guess we can drop that, too. It's been a long time since Tegra
was converted to OF only.

Thierry

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