From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751374AbdAPM27 (ORCPT ); Mon, 16 Jan 2017 07:28:59 -0500 Received: from mx2.suse.de ([195.135.220.15]:46039 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751047AbdAPM26 (ORCPT ); Mon, 16 Jan 2017 07:28:58 -0500 Date: Mon, 16 Jan 2017 13:28:56 +0100 Message-ID: From: Takashi Iwai To: "Arnd Bergmann" Cc: "Jaroslav Kysela" , , , Subject: Re: [PATCH] ALSA: mips: avoid potential uninitialized variable use In-Reply-To: <20170116110517.3833976-1-arnd@arndb.de> References: <20170116110517.3833976-1-arnd@arndb.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.1 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 16 Jan 2017 12:04:56 +0100, Arnd Bergmann wrote: > > MIPS allmodconfig results in this warning: > > sound/mips/hal2.c: In function 'hal2_gain_get': > sound/mips/hal2.c:224:35: error: 'r' may be used uninitialized in this function [-Werror=maybe-uninitialized] > sound/mips/hal2.c:223:35: error: 'l' may be used uninitialized in this function [-Werror=maybe-uninitialized] > sound/mips/hal2.c: In function 'hal2_gain_put': > sound/mips/hal2.c:260:13: error: 'new' may be used uninitialized in this function [-Werror=maybe-uninitialized] > sound/mips/hal2.c:260:13: error: 'old' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > It's easy enough to avoid by adding a 'default' clause to the switch > statements here. I assume that in practice no other case can happen, > but adding a default puts us on the safe side and shuts up the warnings. Well, these cases are logical errors that must not happen, so returning an error would be a "safer", IMO. thanks, Takashi > > Signed-off-by: Arnd Bergmann > --- > sound/mips/hal2.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/sound/mips/hal2.c b/sound/mips/hal2.c > index ede449f0b50d..0af4f7a9b3e7 100644 > --- a/sound/mips/hal2.c > +++ b/sound/mips/hal2.c > @@ -219,6 +219,9 @@ static int hal2_gain_get(struct snd_kcontrol *kcontrol, > l = (tmp >> H2I_C2_L_GAIN_SHIFT) & 15; > r = (tmp >> H2I_C2_R_GAIN_SHIFT) & 15; > break; > + default: > + l = 0; > + r = 0; > } > ucontrol->value.integer.value[0] = l; > ucontrol->value.integer.value[1] = r; > @@ -256,6 +259,9 @@ static int hal2_gain_put(struct snd_kcontrol *kcontrol, > new |= (r << H2I_C2_R_GAIN_SHIFT); > hal2_i_write32(hal2, H2I_ADC_C2, new); > break; > + default: > + new = 0; > + old = 0; > } > return old != new; > } > -- > 2.9.0 > >