Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933111AbcDYRbP (ORCPT ); Mon, 25 Apr 2016 13:31:15 -0400 Received: from mail.savoirfairelinux.com ([208.88.110.44]:48036 "EHLO mail.savoirfairelinux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932619AbcDYRbN convert rfc822-to-8bit (ORCPT ); Mon, 25 Apr 2016 13:31:13 -0400 From: Vivien Didelot To: Geert Uytterhoeven Cc: "David S. Miller" , "netdev\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" Subject: Re: [PATCH] [RFC] net: dsa: mv88e6xxx: Pre-initialize err in mv88e6xxx_port_bridge_join() In-Reply-To: References: <1461570761-12187-1-git-send-email-geert@linux-m68k.org> <87r3dtybm8.fsf@ketchup.mtl.sfl> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-unknown-linux-gnu) Date: Mon, 25 Apr 2016 13:31:09 -0400 Message-ID: <87vb35a942.fsf@ketchup.mtl.sfl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1316 Lines: 37 Hi Geert, Geert Uytterhoeven writes: > On Mon, Apr 25, 2016 at 5:03 PM, Vivien Didelot > wrote: >> Geert Uytterhoeven writes: >>> drivers/net/dsa/mv88e6xxx.c: In function ‘mv88e6xxx_port_bridge_join’: >>> drivers/net/dsa/mv88e6xxx.c:2184: warning: ‘err’ may be used uninitialized in this function >> >> Interesting, I don't have those warnings on 207afda1b5036009... > > It depends on the compiler version (still using 4.1.2) and options. > >>> If netdev_notifier_changeupper_info.upper_dev is ever NULL, the bridge >>> parameter will be NULL too, and the function will return an >>> uninitialized value. >>> >>> Pre-initialize err to zero to fix this. >>> >>> Fixes: 207afda1b5036009 ("net: dsa: mv88e6xxx: share the same default FDB") >>> Signed-off-by: Geert Uytterhoeven >>> --- >>> Can this actually happen? >> >> bridge cannot be NULL here. Also ps->ports[port].bridge_dev is assigned >> to it before entering the for loop, so _mv88e6xxx_port_based_vlan_map >> will be called at least for this port. > > But there's no way the compiler can know that... Or maybe it can in new configurations. Anyway, this fix doesn't hurt, with a relevant commit message, I'd ack it. Thanks, Vivien