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=-17.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 1E7EAC433E0 for ; Thu, 25 Feb 2021 15:50:15 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BFDFB64F13 for ; Thu, 25 Feb 2021 15:50:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BFDFB64F13 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.89842.169632 (Exim 4.92) (envelope-from ) id 1lFItx-0001To-50; Thu, 25 Feb 2021 15:50:05 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 89842.169632; Thu, 25 Feb 2021 15:50:05 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lFItw-0001TI-Ux; Thu, 25 Feb 2021 15:50:04 +0000 Received: by outflank-mailman (input) for mailman id 89842; Thu, 25 Feb 2021 15:50:04 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lFItw-0001Kf-1a for xen-devel@lists.xenproject.org; Thu, 25 Feb 2021 15:50:04 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 0571cfaf-47d8-457c-bad8-be2127c852a5; Thu, 25 Feb 2021 15:50:03 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6E437AF6F; Thu, 25 Feb 2021 15:50:02 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 0571cfaf-47d8-457c-bad8-be2127c852a5 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1614268202; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=pMucLcc56VqB9XHOjU5pnfmJJn7cw8SR0wP2s0f41So=; b=m4E/THIfEmiLFUtrLisy3y4MulXF0Hn74tAG/ulYjoiWMHR8j7Kqr3yazdNAd7Xlvrxt6e IDWXmO0BW/9vX04082mZnyLtdqyUeqk65wddwHOC5BT6ZkXWnyQvhNdOOrS6uaLsE1cVIm 4PivqC1PGRt1oxvss9LpdTAAEqmMmHY= Subject: Re: [PATCH for-next 3/6] xen/sched: Fix build when NR_CPUS == 1 To: Connor Davis Cc: Bobby Eshleman , George Dunlap , Dario Faggioli , xen-devel@lists.xenproject.org References: From: Jan Beulich Message-ID: Date: Thu, 25 Feb 2021 16:50:02 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 25.02.2021 16:24, Connor Davis wrote: > Return from cpu_schedule_up when either cpu is 0 or > NR_CPUS == 1. This fixes the following: > > core.c: In function 'cpu_schedule_up': > core.c:2769:19: error: array subscript 1 is above array bounds > of 'struct vcpu *[1]' [-Werror=array-bounds] > 2769 | if ( idle_vcpu[cpu] == NULL ) > | > > Signed-off-by: Connor Davis > --- > xen/common/sched/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c > index 9745a77eee..f5ec65bf9b 100644 > --- a/xen/common/sched/core.c > +++ b/xen/common/sched/core.c > @@ -2763,7 +2763,7 @@ static int cpu_schedule_up(unsigned int cpu) > cpumask_set_cpu(cpu, &sched_res_mask); > > /* Boot CPU is dealt with later in scheduler_init(). */ > - if ( cpu == 0 ) > + if ( cpu == 0 || NR_CPUS == 1 ) > return 0; > > if ( idle_vcpu[cpu] == NULL ) I'm not convinced a compiler warning is due here, and in turn I'm not sure we want/need to work around this the way you do. First question is whether that's just a specific compiler version that's flawed. If it's not just a special case (e.g. some unreleased version) we may want to think of possible alternatives - the addition looks really odd to me. Jan