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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F17EEC38145 for ; Tue, 6 Sep 2022 22:19:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229668AbiIFWTj (ORCPT ); Tue, 6 Sep 2022 18:19:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229703AbiIFWTg (ORCPT ); Tue, 6 Sep 2022 18:19:36 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBBF77641 for ; Tue, 6 Sep 2022 15:19:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662502774; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=K111mClAVKBb8x/inphQinCwssocvNLnhBz225LosPQ=; b=TRuNGHnPrIh8x5tCULsTXazWhTJr80KoSnZc5ungEAx0s7HxuLqTyrKMHD8lAXum8bGaOz UBaVWaVhFTe62AA/qUznDWtbEw+8/YO5xWTCr58QPnFMpLn0ZO0zM943jmlJPGMeD4qCO6 JWLOGl1eVPSRNvywmq9V/1BxAJE7f6A= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-286-sM63FM_uPU-5bcyz9UgM3g-1; Tue, 06 Sep 2022 18:19:29 -0400 X-MC-Unique: sM63FM_uPU-5bcyz9UgM3g-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8C893803301; Tue, 6 Sep 2022 22:19:25 +0000 (UTC) Received: from lorien.usersys.redhat.com (unknown [10.22.32.243]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D61ED2166B26; Tue, 6 Sep 2022 22:19:24 +0000 (UTC) Date: Tue, 6 Sep 2022 18:19:23 -0400 From: Phil Auld To: Yury Norov Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , "Rafael J . Wysocki" , Barry Song <21cnbao@gmail.com>, Tian Tao , feng xiangjun , stable@vger.kernel.org Subject: Re: [PATCH v2] drivers/base: Fix unsigned comparison to -1 in CPUMAP_FILE_MAX_BYTES Message-ID: References: <20220906203542.1796629-1-pauld@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Sep 06, 2022 at 01:59:53PM -0700 Yury Norov wrote: > On Tue, Sep 06, 2022 at 04:35:42PM -0400, Phil Auld wrote: > > As PAGE_SIZE is unsigned long, -1 > PAGE_SIZE when NR_CPUS <= 3. > > This leads to very large file sizes: > > > > topology$ ls -l > > total 0 > > -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 core_cpus > > -r--r--r-- 1 root root 4096 Sep 5 11:59 core_cpus_list > > -r--r--r-- 1 root root 4096 Sep 5 10:58 core_id > > -r--r--r-- 1 root root 18446744073709551615 Sep 5 10:10 core_siblings > > -r--r--r-- 1 root root 4096 Sep 5 11:59 core_siblings_list > > -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 die_cpus > > -r--r--r-- 1 root root 4096 Sep 5 11:59 die_cpus_list > > -r--r--r-- 1 root root 4096 Sep 5 11:59 die_id > > -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 package_cpus > > -r--r--r-- 1 root root 4096 Sep 5 11:59 package_cpus_list > > -r--r--r-- 1 root root 4096 Sep 5 10:58 physical_package_id > > -r--r--r-- 1 root root 18446744073709551615 Sep 5 10:10 thread_siblings > > -r--r--r-- 1 root root 4096 Sep 5 11:59 thread_siblings_list > > > > Adjust the inequality to catch the case when NR_CPUS is configured > > to a small value. > > > > Fixes: 7ee951acd31a ("drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist") > > Reported-by: feng xiangjun > > Signed-off-by: Phil Auld > > Cc: Greg Kroah-Hartman > > Cc: "Rafael J. Wysocki" > > Cc: Yury Norov > > Cc: stable@vger.kernel.org > > Cc: feng xiangjun > > Applied on bitmap-for-next. Thanks! > Great, thanks! > > --- > > > > v2: Remove the +/-1 completely from the test since it will produce the > > same results, and remove some extra parentheses. > > > > include/linux/cpumask.h | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > > index bd047864c7ac..e8ad12b5b9d2 100644 > > --- a/include/linux/cpumask.h > > +++ b/include/linux/cpumask.h > > @@ -1127,9 +1127,10 @@ cpumap_print_list_to_buf(char *buf, const struct cpumask *mask, > > * cover a worst-case of every other cpu being on one of two nodes for a > > * very large NR_CPUS. > > * > > - * Use PAGE_SIZE as a minimum for smaller configurations. > > + * Use PAGE_SIZE as a minimum for smaller configurations while avoiding > > + * unsigned comparison to -1. > > */ > > -#define CPUMAP_FILE_MAX_BYTES ((((NR_CPUS * 9)/32 - 1) > PAGE_SIZE) \ > > +#define CPUMAP_FILE_MAX_BYTES (((NR_CPUS * 9)/32 > PAGE_SIZE) \ > > ? (NR_CPUS * 9)/32 - 1 : PAGE_SIZE) > > #define CPULIST_FILE_MAX_BYTES (((NR_CPUS * 7)/2 > PAGE_SIZE) ? (NR_CPUS * 7)/2 : PAGE_SIZE) > > > > -- > > 2.31.1 > --