From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3ACEFC43381 for ; Mon, 11 Mar 2019 09:16:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14432206BA for ; Mon, 11 Mar 2019 09:16:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727017AbfCKJQJ (ORCPT ); Mon, 11 Mar 2019 05:16:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39832 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726682AbfCKJQJ (ORCPT ); Mon, 11 Mar 2019 05:16:09 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 65CC187624; Mon, 11 Mar 2019 09:16:09 +0000 (UTC) Received: from localhost (unknown [10.40.205.57]) by smtp.corp.redhat.com (Postfix) with ESMTP id E067019C71; Mon, 11 Mar 2019 09:16:08 +0000 (UTC) Date: Mon, 11 Mar 2019 10:16:08 +0100 From: Stanislaw Gruszka To: Kangjie Lu Cc: pakki001@umn.edu, Kalle Valo , "David S. Miller" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: iwlegacy: fix potential NULL pointer dereferences Message-ID: <20190311091607.GC3310@redhat.com> References: <20190311073758.31038-1-kjlu@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190311073758.31038-1-kjlu@umn.edu> User-Agent: Mutt/1.8.3 (2017-05-23) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 11 Mar 2019 09:16:09 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Mar 11, 2019 at 02:37:57AM -0500, Kangjie Lu wrote: > In case create_singlethread_workqueue fails, the fix immediately > return to avoid NULL pointer dereferences. > > Signed-off-by: Kangjie Lu > --- > drivers/net/wireless/intel/iwlegacy/3945-mac.c | 2 ++ > drivers/net/wireless/intel/iwlegacy/4965-mac.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/drivers/net/wireless/intel/iwlegacy/3945-mac.c b/drivers/net/wireless/intel/iwlegacy/3945-mac.c > index 271977f7fbb0..d23ee2ca0c8e 100644 > --- a/drivers/net/wireless/intel/iwlegacy/3945-mac.c > +++ b/drivers/net/wireless/intel/iwlegacy/3945-mac.c > @@ -3403,6 +3403,8 @@ static void > il3945_setup_deferred_work(struct il_priv *il) > { > il->workqueue = create_singlethread_workqueue(DRV_NAME); > + if (!il->workqueue) > + return; This is not full fix since we will crash later without setup various structures in il3945_setup_deferred_work. The driver is pretty much legacy and worked for decade (or maybe more) without NULL dereference of il->workqueue. I do not see need to fix _potential_ problems as fix can introduce more harm than good. Stanislaw