From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mout.kundenserver.de ([212.227.126.135]:52689 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935350AbcJ0PQT (ORCPT ); Thu, 27 Oct 2016 11:16:19 -0400 From: Arnd Bergmann To: Jarod Wilson 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 Date: Thu, 27 Oct 2016 17:09:28 +0200 Message-ID: <20018611.sQONvMWYdP@wuerfel> In-Reply-To: <20161027141327.GE42084@redhat.com> References: <20161027140835.2345937-1-arnd@arndb.de> <20161027141327.GE42084@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="UTF-8" Sender: linux-media-owner@vger.kernel.org List-ID: On Thursday, October 27, 2016 10:13:27 AM CEST Jarod Wilson wrote: > 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". > Yes, I sent a v2 now, thanks for taking a look. I assume this means you have no other objections to the patch? Arnd