linux-kernel - Re: wireless: fix bogus maybe-uninitialized warning

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Message-Id: <20161117064655.B2591615D8@smtp.codeaurora.org>
Date:   Thu, 17 Nov 2016 06:46:55 +0000 (UTC)
From:   Kalle Valo <kvalo@...eaurora.org>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     Kalle Valo <kvalo@....qualcomm.com>,
        Stanislav Yakovlev <stas.yakovlev@...il.com>,
        Jouni Malinen <j@...fi>,
        Johannes Berg <johannes@...solutions.net>,
        "David S. Miller" <davem@...emloft.net>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org
Subject: Re: wireless: fix bogus maybe-uninitialized warning

Arnd Bergmann <arnd@...db.de> wrote:
> The hostap_80211_rx() function is supposed to set up the mac addresses
> for four possible cases, based on two bits of input data. For
> some reason, gcc decides that it's possible that none of the these
> four cases apply and the addresses remain uninitialized:
> 
> drivers/net/wireless/intersil/hostap/hostap_80211_rx.c: In function ‘hostap_80211_rx’:
> arch/x86/include/asm/string_32.h:77:14: warning: ‘src’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> drivers/net/wireless/intel/ipw2x00/libipw_rx.c: In function ‘libipw_rx’:
> arch/x86/include/asm/string_32.h:77:14: error: ‘dst’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> arch/x86/include/asm/string_32.h:78:22: error: ‘*((void *)&dst+4)’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> This warning is clearly nonsense, but changing the last case into
> 'default' makes it obvious to the compiler too, which avoids the
> warning and probably leads to better object code too.
> 
> The same code is duplicated several times in the kernel, so this
> patch uses the same workaround for all copies. The exact configuration
> was hit only very rarely in randconfig builds and I only saw it
> in three drivers, but I assume that all of them are potentially
> affected, and it's better to keep the code consistent.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

Patch applied to wireless-drivers-next.git, thanks.

10f3366b4d89 wireless: fix bogus maybe-uninitialized warning

-- 
https://patchwork.kernel.org/patch/9392385/

Documentation about submitting wireless patches and checking status
from patchwork:

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches