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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 2A8AAC43331 for ; Wed, 1 Apr 2020 20:30:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00C6420737 for ; Wed, 1 Apr 2020 20:30:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732746AbgDAUaP (ORCPT ); Wed, 1 Apr 2020 16:30:15 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35770 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732337AbgDAUaP (ORCPT ); Wed, 1 Apr 2020 16:30:15 -0400 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jJk01-0000vF-O5; Wed, 01 Apr 2020 22:30:09 +0200 Received: by nanos.tec.linutronix.de (Postfix, from userid 1000) id A54DA101177; Wed, 1 Apr 2020 22:30:08 +0200 (CEST) From: Thomas Gleixner To: Peter Xu , linux-kernel@vger.kernel.org Cc: peterx@redhat.com, Ming Lei , Ingo Molnar , Peter Zijlstra , Juri Lelli , Luiz Capitulino Subject: Re: [PATCH] sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters In-Reply-To: <20200204161639.267026-1-peterx@redhat.com> References: <20200204161639.267026-1-peterx@redhat.com> Date: Wed, 01 Apr 2020 22:30:08 +0200 Message-ID: <87d08rosof.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Xu writes: > @@ -169,8 +169,12 @@ static int __init housekeeping_isolcpus_setup(char *str) > continue; > } > > - pr_warn("isolcpus: Error, unknown flag\n"); > - return 0; > + str = strchr(str, ','); > + if (str) > + /* Skip unknown sub-parameter */ > + str++; > + else > + return 0; Just looked at it again because I wanted to apply this and contrary to last time I figured out that this is broken: isolcpus=nohz,domain1,3,5 is a malformatted option, but the above will make it "valid" and result in: HK_FLAG_TICK and a cpumask of 3,5. The flags are required to be is_alpha() only. So you want something like the untested below. Hmm? Thanks, tglx 8<--------------- --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -149,6 +149,8 @@ static int __init housekeeping_nohz_full static int __init housekeeping_isolcpus_setup(char *str) { unsigned int flags = 0; + char *par; + int len; while (isalpha(*str)) { if (!strncmp(str, "nohz,", 5)) { @@ -169,8 +171,17 @@ static int __init housekeeping_isolcpus_ continue; } - pr_warn("isolcpus: Error, unknown flag\n"); - return 0; + /* + * Skip unknown sub-parameter and validate that it is not + * containing an invalid character. + */ + for (par = str, len = 0; isalpha(*str); str++, len++); + if (*str != ',') { + pr_warn("isolcpus: Invalid flag %*s\n", len, par); + return 0; + } + pr_info("isolcpus: Skipped unknown flag %*s\n", len, par); + str++; } /* Default behaviour for isolcpus without flags */