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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 0EA01ECDE5F for ; Mon, 23 Jul 2018 08:37:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7C4020647 for ; Mon, 23 Jul 2018 08:37:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="KZOFkwlO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7C4020647 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388104AbeGWJhN (ORCPT ); Mon, 23 Jul 2018 05:37:13 -0400 Received: from merlin.infradead.org ([205.233.59.134]:36824 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387972AbeGWJhN (ORCPT ); Mon, 23 Jul 2018 05:37:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=3t1ILcP0waxWz0icApDAfgvIFrJ104KU9yTd0GACuM8=; b=KZOFkwlOqaKkc56wBeb2t7eDb NMWOZOEQ+6SXspuzGO3JL1Q3JWgmkEJD5dNDnPpFb5ck+bynTOK2NcBoQ9jHrr46n0pwrB3+qrR4F jtvza+9+IRpcvvb34fmBw6dY3WsnUZhLsp8XXPglWXK8Wr9z9ocked1eyVuXvwbwW0YtgC+hTqBaO cZTrgcODlmEfD2J32Tc/rOm/hYPJyvUpfn8UpFmV+feHCZJSYLfi/l5NwkZIzfAImfGLyrRL3eCAS o60cV1Vfu9M/LTldn7HIrrvzldk63HryokiVoQY+LiMBGRYREX0lgbswLVfbnD1gO7KYa0MjOvXYG Hu3BgcTMA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fhWL3-0004rC-6y; Mon, 23 Jul 2018 08:37:05 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2EEE620275F47; Mon, 23 Jul 2018 10:37:02 +0200 (CEST) Date: Mon, 23 Jul 2018 10:37:02 +0200 From: Peter Zijlstra To: Yi Wang Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, jiang.biao2@zte.com.cn, zhong.weidong@zte.com.cn Subject: Re: [PATCH] sched/topology: check variable group before dereferenced Message-ID: <20180723083702.GW2494@hirez.programming.kicks-ass.net> References: <1532319547-33335-1-git-send-email-wang.yi59@zte.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1532319547-33335-1-git-send-email-wang.yi59@zte.com.cn> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 23, 2018 at 12:19:07PM +0800, Yi Wang wrote: > The variable group in sched_domain_debug_one() is not checked > when firstly used in cpumask_test_cpu(cpu, sched_group_span(group)), > but it maybe NULL(checked later in the following while loop) and may > cause NULL pointer dereference without checking. We need to check it > before using to avoid NULL dereference. It being NULL really is a fairly severe error in construction; but sure. This patch won't hurt. > Signed-off-by: Yi Wang > Reviewed-by: Jiang Biao > --- > kernel/sched/topology.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 5ac724b..c7cf87c 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -53,7 +53,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, > printk(KERN_ERR "ERROR: domain->span does not contain " > "CPU%d\n", cpu); > } > - if (!cpumask_test_cpu(cpu, sched_group_span(group))) { > + if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) { > printk(KERN_ERR "ERROR: domain->groups does not contain" > " CPU%d\n", cpu); > } > -- > 1.8.3.1 >