Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933126AbcDYQfA (ORCPT ); Mon, 25 Apr 2016 12:35:00 -0400 Received: from mail-ig0-f195.google.com ([209.85.213.195]:35336 "EHLO mail-ig0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933050AbcDYQe6 convert rfc822-to-8bit (ORCPT ); Mon, 25 Apr 2016 12:34:58 -0400 MIME-Version: 1.0 In-Reply-To: <87r3dtybm8.fsf@ketchup.mtl.sfl> References: <1461570761-12187-1-git-send-email-geert@linux-m68k.org> <87r3dtybm8.fsf@ketchup.mtl.sfl> Date: Mon, 25 Apr 2016 18:34:57 +0200 X-Google-Sender-Auth: kdS-bMm5KsENKotV8IPLNz7WMLI Message-ID: Subject: Re: [PATCH] [RFC] net: dsa: mv88e6xxx: Pre-initialize err in mv88e6xxx_port_bridge_join() From: Geert Uytterhoeven To: Vivien Didelot Cc: "David S. Miller" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" 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: 1439 Lines: 39 Hi Vivien, 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... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds