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=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,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 2DF20C6786F for ; Tue, 30 Oct 2018 14:47:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01B382075D for ; Tue, 30 Oct 2018 14:47:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01B382075D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com 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 S1727231AbeJ3Xlg (ORCPT ); Tue, 30 Oct 2018 19:41:36 -0400 Received: from mga07.intel.com ([134.134.136.100]:52727 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725853AbeJ3Xlf (ORCPT ); Tue, 30 Oct 2018 19:41:35 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Oct 2018 07:47:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,444,1534834800"; d="scan'208";a="101927962" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga004.fm.intel.com with ESMTP; 30 Oct 2018 07:47:49 -0700 Date: Tue, 30 Oct 2018 08:45:27 -0600 From: Keith Busch To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner Subject: Re: [PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs Message-ID: <20181030144527.GB18906@localhost.localdomain> References: <20181029163738.10172-1-axboe@kernel.dk> <20181029163738.10172-12-axboe@kernel.dk> <20181030142601.GA18906@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 30, 2018 at 08:36:35AM -0600, Jens Axboe wrote: > On 10/30/18 8:26 AM, Keith Busch wrote: > > On Mon, Oct 29, 2018 at 10:37:35AM -0600, Jens Axboe wrote: > >> diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c > >> index f4f29b9d90ee..2046a0f0f0f1 100644 > >> --- a/kernel/irq/affinity.c > >> +++ b/kernel/irq/affinity.c > >> @@ -180,6 +180,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) > >> int curvec, usedvecs; > >> cpumask_var_t nmsk, npresmsk, *node_to_cpumask; > >> struct cpumask *masks = NULL; > >> + int i, nr_sets; > >> > >> /* > >> * If there aren't any vectors left after applying the pre/post > >> @@ -210,10 +211,23 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) > >> get_online_cpus(); > >> build_node_to_cpumask(node_to_cpumask); > >> > >> - /* Spread on present CPUs starting from affd->pre_vectors */ > >> - usedvecs = irq_build_affinity_masks(affd, curvec, affvecs, > >> - node_to_cpumask, cpu_present_mask, > >> - nmsk, masks); > >> + /* > >> + * Spread on present CPUs starting from affd->pre_vectors. If we > >> + * have multiple sets, build each sets affinity mask separately. > >> + */ > >> + nr_sets = affd->nr_sets; > >> + if (!nr_sets) > >> + nr_sets = 1; > >> + > >> + for (i = 0, usedvecs = 0; i < nr_sets; i++) { > >> + int this_vecs = affd->sets ? affd->sets[i] : affvecs; > >> + int nr; > >> + > >> + nr = irq_build_affinity_masks(affd, curvec, this_vecs, > >> + node_to_cpumask, cpu_present_mask, > >> + nmsk, masks + usedvecs); > >> + usedvecs += nr; > >> + } > > > > > > While the code below returns the appropriate number of possible vectors > > when a set requested too many, the above code is still using the value > > from the set, which may exceed 'nvecs' used to kcalloc 'masks', so > > 'masks + usedvecs' may go out of bounds. > > How so? nvecs must the max number of vecs, the sum of the sets can't > exceed that value. 'nvecs' is what irq_calc_affinity_vectors() returns, which is the min of either the requested max or the sum of the set, and the sum of the set isn't guaranteed to be the smaller value.