linux-kernel - Re: [PATCH] nl80211: avoid "wdev

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Date:	Thu, 31 Jan 2013 21:51:37 +0100
From:	Johannes Berg <johannes@...solutions.net>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	"John W. Linville" <linville@...driver.com>,
	"David S. Miller" <davem@...emloft.net>,
	linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, Stephen Warren <swarren@...dia.com>
Subject: Re: [PATCH] nl80211: avoid "wdev_id may be used uninitialized"

On Wed, 2013-01-30 at 09:49 -0700, Stephen Warren wrote:
> On 01/30/2013 12:57 AM, Johannes Berg wrote:
> > On Tue, 2013-01-29 at 17:11 -0700, Stephen Warren wrote:
> >> From: Stephen Warren <swarren@...dia.com>
> >>
> >> Silence the following:
> >> net/wireless/nl80211.c: In function '__cfg80211_wdev_from_attrs.clone.119':
> >> net/wireless/nl80211.c:57:6: warning: 'wdev_id' may be used uninitialized in this function
> >>
> >> ... by always initializing wdev_id to zero. I assume that wiphy_idx and
> >> ifidx are set to -1 for similar reasons, so this change simply propagates
> >> the same workaround.
> >>
> >> In practice, this warning is false, since wdev_id is both set and used
> >> under the condition if (have_wdev_id). However, at least my compiler
> >> can't be coerced into realizing this; almost any code between the if
> >> blocks that set and use the variable causes this warning.
> > 
> > I don't see this warning? What compiler are you using?
> 
> I'm using gcc-4.5.3 for ARM. I checked with gcc-4.6.3 and gcc-4.7.2 and
> indeed I don't see the warning there.

Interesting. So should I keep it or remove it? I guess in this
particular instance it doesn't matter all that much. In other cases I'd
be more against changing it I guess.

johannes

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