From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wm0-f42.google.com ([74.125.82.42]:36511 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938553AbcJ0ONd (ORCPT ); Thu, 27 Oct 2016 10:13:33 -0400 Received: by mail-wm0-f42.google.com with SMTP id b80so36769095wme.1 for ; Thu, 27 Oct 2016 07:13:32 -0700 (PDT) Date: Thu, 27 Oct 2016 10:13:27 -0400 From: Jarod Wilson To: Arnd Bergmann Cc: Mauro Carvalho Chehab , Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [media] dvb: avoid warning in dvb_net Message-ID: <20161027141327.GE42084@redhat.com> References: <20161027140835.2345937-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20161027140835.2345937-1-arnd@arndb.de> Sender: linux-media-owner@vger.kernel.org List-ID: On Thu, Oct 27, 2016 at 03:57:41PM +0200, Arnd Bergmann wrote: > With gcc-5 or higher on x86, we can get a bogus warning in the > dvb-net code: > > drivers/media/dvb-core/dvb_net.c: In function ‘dvb_net_ule’: > arch/x86/include/asm/string_32.h:77:14: error: ‘dest_addr’ may be used uninitialized in this function [-Werror=maybe-uninitialized] > drivers/media/dvb-core/dvb_net.c:633:8: note: ‘dest_addr’ was declared here > > The problem here is that gcc doesn't track all of the conditions > to prove it can't end up copying uninitialized data. > This changes the logic around so we zero out the destination > address earlier when we determine that it is not set here. > This allows the compiler to figure it out. > > Signed-off-by: Arnd Bergmann > --- > drivers/media/dvb-core/dvb_net.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/drivers/media/dvb-core/dvb_net.c b/drivers/media/dvb-core/dvb_net.c > index 088914c4623f..f1b416de9dab 100644 > --- a/drivers/media/dvb-core/dvb_net.c > +++ b/drivers/media/dvb-core/dvb_net.c > @@ -688,6 +688,9 @@ static void dvb_net_ule( struct net_device *dev, const u8 *buf, size_t buf_len ) > ETH_ALEN); > skb_pull(priv->ule_skb, ETH_ALEN); > } > + } else { > + /* othersie use zero destination address */ I'm assuming you meant "otherwise" there instead of "othersie". -- Jarod Wilson jarod@redhat.com