linux-kernel - Re: [PATCH] arch: cris: arch-v32: drivers: axisflashmap.c: Cleaning up inconsistent NULL checks

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Message-ID: <20140526080902.GL9198@axis.com>
Date:	Mon, 26 May 2014 10:09:02 +0200
From:	Jesper Nilsson <jesper.nilsson@...s.com>
To:	Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
Cc:	Jesper Nilsson <jespern@...s.com>,
	Mikael Starvik <starvik@...s.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	linux-cris-kernel <linux-cris-kernel@...s.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arch: cris: arch-v32: drivers: axisflashmap.c:
 Cleaning up inconsistent NULL checks

On Fri, May 23, 2014 at 06:40:17PM +0200, Rickard Strandqvist wrote:
> Hej Jesper!

Tjo!

> But in several other place in the feature ensures that main_mtd is not NULL.
> (That's what cppcheck base their misjudgment on too)
>
> Then all these checks are unnecessary?

No, it is still necessary to check for NULL, however as I wrote in my reply,
we do check for ptable_head, which is only set if main_mtd is set.

> You should know, looks like you've written most of the code in 2007 :)
>
> Best regards
> Rickard Strandqvist

/Jesper

> 2014-05-23 9:00 GMT+02:00 Jesper Nilsson <jesper.nilsson@...s.com>:
> > On Fri, May 23, 2014 at 12:00:09AM +0200, Rickard Strandqvist wrote:
> >> Cleaning up inconsistent NULL checks.
> >> There is otherwise a risk of a possible null pointer dereference.
> >>
> >> Was largely found by using a static code analysis program called cppcheck.
> >
> > ... and is a false positive.
> >
> > We can't enter this if-block unless ptable_head is set,
> > which is only set if main_mtd is set.
> >
> > It might be useful to add it anyways, but there's a refactoring
> > needed for the axisflashmaps, so I'll keep it for then.
> >
> > /^JN - Jesper Nilsson
> > --
> >                Jesper Nilsson -- jesper.nilsson@...s.com

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@...s.com
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