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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E3E8ECD11C2 for ; Fri, 5 Apr 2024 14:31:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mvs2GRuXg2lJzXeqpFFdcHxokGDWqPtTIaYWVOk2uUI=; b=W39FkBAyVb9F0I NOqyvzG3mXbDuLb1MWRr2MlB3D4FgYkAxO2zrVNNjRNoc4MvfHqdH00sJRUkMKiT3rutiWarXPjde EoKPIOmit906rcAW/yd2a5fcbD/ci6csM7OCWqta589jHfmCSB/nedF+TieINIxFd3uOKhv6UisOh loodzZapO8+1oyQcFS5ZnnNrOZJzl3JLKoTh5eJujSykj9n4RM7nJ++r0J519w+gIIQ0Pme3d8qgM R05HOAMa0qL9rPRhmP6tYnkH/IGXUrIAIWXSornoD9pjG5wfuhzp9X/daO91KicDa6tOs4W+ivRT8 5vUkBEtrkweFSGjB/DYQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rskaq-00000007TNe-3mAa; Fri, 05 Apr 2024 14:31:00 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rskan-00000007TLt-1PqY for linux-arm-kernel@lists.infradead.org; Fri, 05 Apr 2024 14:30:58 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 22A4CFEC; Fri, 5 Apr 2024 07:31:26 -0700 (PDT) Received: from [10.57.54.111] (unknown [10.57.54.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7D3883F7B4; Fri, 5 Apr 2024 07:30:53 -0700 (PDT) Message-ID: <5ab9bd5b-87e9-4e09-af49-7f15b0cc48d5@arm.com> Date: Fri, 5 Apr 2024 15:30:51 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/9] perf/arm-cmn: Avoid explicit cpumask var allocation from stack Content-Language: en-GB To: Dawei Li , will@kernel.org, mark.rutland@arm.com Cc: xueshuai@linux.alibaba.com, renyu.zj@linux.alibaba.com, yangyicong@hisilicon.com, jonathan.cameron@huawei.com, andersson@kernel.org, konrad.dybcio@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org References: <20240402105610.1695644-1-dawei.li@shingroup.cn> <20240402105610.1695644-3-dawei.li@shingroup.cn> From: Robin Murphy In-Reply-To: <20240402105610.1695644-3-dawei.li@shingroup.cn> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240405_073057_464714_169DC132 X-CRM114-Status: GOOD ( 16.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2024-04-02 11:56 am, Dawei Li wrote: > For CONFIG_CPUMASK_OFFSTACK=y kernel, explicit allocation of cpumask > variable on stack is not recommended since it can cause potential stack > overflow. > > Instead, kernel code should always use *cpumask_var API(s) to allocate > cpumask var in config- neutral way, leaving allocation strategy to > CONFIG_CPUMASK_OFFSTACK. > > Use *cpumask_var API(s) to address it. I think the temporary mask may simply be redundant anyway. It seems like I may have misunderstood, and cpumask_of_node() actually only covers online CPUs already. Thanks, Robin. > Signed-off-by: Dawei Li > --- > drivers/perf/arm-cmn.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c > index 7ef9c7e4836b..7278fd72d3da 100644 > --- a/drivers/perf/arm-cmn.c > +++ b/drivers/perf/arm-cmn.c > @@ -1949,21 +1949,26 @@ static int arm_cmn_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_no > { > struct arm_cmn *cmn; > unsigned int target; > + cpumask_var_t mask; > int node; > - cpumask_t mask; > > cmn = hlist_entry_safe(cpuhp_node, struct arm_cmn, cpuhp_node); > if (cpu != cmn->cpu) > return 0; > > + if (!alloc_cpumask_var(&mask, GFP_KERNEL)) > + return 0; > + > node = dev_to_node(cmn->dev); > - if (cpumask_and(&mask, cpumask_of_node(node), cpu_online_mask) && > - cpumask_andnot(&mask, &mask, cpumask_of(cpu))) > - target = cpumask_any(&mask); > + if (cpumask_and(mask, cpumask_of_node(node), cpu_online_mask) && > + cpumask_andnot(mask, mask, cpumask_of(cpu))) > + target = cpumask_any(mask); > else > target = cpumask_any_but(cpu_online_mask, cpu); > if (target < nr_cpu_ids) > arm_cmn_migrate(cmn, target); > + > + free_cpumask_var(mask); > return 0; > } > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel