From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] pinctrl: sunxi: fix theoretical uninitialized variable access Date: Thu, 17 Nov 2016 10:24:28 +0100 Message-ID: <6865471.komOtxkTtZ@wuerfel> References: <20161116141841.2030776-1-arnd@arndb.de> <20161116203358.midi7vmaqirpywtt@lukather> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mout.kundenserver.de ([212.227.126.135]:51439 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751762AbcKQJZE (ORCPT ); Thu, 17 Nov 2016 04:25:04 -0500 In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Linus Walleij Cc: Maxime Ripard , Chen-Yu Tsai , "linux-gpio@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" On Thursday, November 17, 2016 10:08:28 AM CET Linus Walleij wrote: > On Wed, Nov 16, 2016 at 9:33 PM, Maxime Ripard > wrote: > > > On Wed, Nov 16, 2016 at 03:18:18PM +0100, Arnd Bergmann wrote: > >> gcc warns about a way that it could use an uninitialized variable: > >> > >> drivers/pinctrl/sunxi/pinctrl-sunxi.c: In function 'sunxi_pinctrl_init': > >> drivers/pinctrl/sunxi/pinctrl-sunxi.c:1191:8: error: 'best_div' may be used uninitialized in this function [-Werror=maybe-uninitialized] > >> > >> This cannot really happen except if 'freq' is UINT_MAX and 'clock' is > >> zero, and both of these are forbidden. To shut up the warning anyway, > >> this changes the logic to initialize the return code to the first > >> divider value before looking at the others. > >> > >> Fixes: 7c926492d38a ("pinctrl: sunxi: Add support for interrupt debouncing") > >> Signed-off-by: Arnd Bergmann > > > > Thanks for that patch. > > > > Just out of curiosity, which gcc gives those warnings? I have 6.2 and > > it didn't output anything.. > > Context: Arnd re-enabled -Werror=maybe-uninitialized > in the kernel build and this kind of stuff started to appear so > it needs to be fixed up. Right, it was disabled from linux-4.8-rc1 to linux-4.9-rc4 and is now back in the default builds when using gcc-4.9 or higher. You should get the warning if you test with linux-next or -rc4. Arnd