From patchwork Wed Apr 3 12:51:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dawei Li X-Patchwork-Id: 13616056 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 0D918CD128A for ; Wed, 3 Apr 2024 12:54:19 +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-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SGRv6m6fZsdYm+WjdB42HDfSxmIcx8uaukdkHC9wcIs=; b=eYj0SyQnTuoStU aYXeOY6PvYYQO+RfAkogYPArVEonY9eCKKTECpd6HVvPojcp9cP/5NG7mWYT31ZFm4DAbkqhIH7KK p5BP3bojW6bxHJw/1z7Bp8wh7VNHyOK0DurT8rweE1/3PdLh20b6at2RRIcuBiZWOHbmgp0ncsOg6 pvjvH464fOFLYBZTazFQU0UqK5i6MQF2+w9ZWHY1xI883GEubqCA0OQ09l9SV8QAqEJSWUwrbgR6f uFUZNFcRVikq4JrAjOC1c05AV1ctYE2sYr+kWo2+jyB5f/5+2Au9Z1dJR+Vw7MY7CVeJ92M3SWqkD VI7LTMAy9/wG1ZiX9rFA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs080-0000000G27s-0vPO; Wed, 03 Apr 2024 12:54:08 +0000 Received: from smtpbgsg1.qq.com ([54.254.200.92]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs07x-0000000G1rL-0N6p for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2024 12:54:06 +0000 X-QQ-mid: bizesmtpsz13t1712148751thjp14 X-QQ-Originating-IP: PN96WD6+s0f0fHNZoIaqwlrHcfY0nVQajJhi8FUfFuM= Received: from localhost ( [112.0.147.175]) by bizesmtp.qq.com (ESMTP) with id ; Wed, 03 Apr 2024 20:52:30 +0800 (CST) X-QQ-SSF: 01400000000000704000000A0000000 X-QQ-FEAT: zcLa5zqvhxgf/5JXWZ8twfXFCazlSAsrySVLuhjEZMYToUkKWNsAJmBBYfDe+ NsLkXC+chAgf1GKnj0xs+cjveEn376+2q5jqMLFhczeZpSps2N19LEoRD2EbL4GsthwKh2A ZyAM+BPRilAQekCh1hGwcIFu4x73e4p44a+fel0VgLqjLCpdTtAIDgjrdSd5diS1y57wy88 hDyTUongOVf12A2X/IV7LhSD94AniI9zUmfBXtROAXHdcHcYaWhLWsEoBZGrY2TnkpQM+My W/ls2X2G2eB/4CVV13mfkN8eKhXbh+2+EZslaoWjqF2Vpw/mamsDazphJq5suJJVWI/apJG AD/bzvFButsgFqs8fNhD38vhGupDFjLpN6Juab9D/+ynsLdXRwsXrr+Bl9JrApdbDjgOxeM oLfxxIRlYsInBfAA6uV2dWzExTT2ldHB X-QQ-GoodBg: 2 X-BIZMAIL-ID: 11098512972322688443 From: Dawei Li To: will@kernel.org, mark.rutland@arm.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk 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, Dawei Li Subject: [PATCH v2 06/10] perf/dwc_pcie: Avoid placing cpumask var on stack Date: Wed, 3 Apr 2024 20:51:05 +0800 Message-Id: <20240403125109.2054881-7-dawei.li@shingroup.cn> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20240403125109.2054881-1-dawei.li@shingroup.cn> References: <20240403125109.2054881-1-dawei.li@shingroup.cn> MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtpsz:shingroup.cn:qybglogicsvrgz:qybglogicsvrgz5a-1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240403_055405_536525_4996D9D7 X-CRM114-Status: GOOD ( 13.38 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. But dynamic allocation in cpuhp's teardown callback is somewhat problematic for if allocation fails(which is unlikely but still possible): - If -ENOMEM is returned to caller, kernel crashes for non-bringup teardown; - If callback pretends nothing happened and returns 0 to caller, it may trap system into an in-consisitent/compromised state; Use newly-introduced cpumask_any_and_but() to address all issues above. It eliminates usage of temporary cpumask var in generic way, no matter how the cpumask var is allocated. Suggested-by: Mark Rutland Signed-off-by: Dawei Li Reviewed-by: Mark Rutland --- drivers/perf/dwc_pcie_pmu.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/perf/dwc_pcie_pmu.c b/drivers/perf/dwc_pcie_pmu.c index 957058ad0099..c5e328f23841 100644 --- a/drivers/perf/dwc_pcie_pmu.c +++ b/drivers/perf/dwc_pcie_pmu.c @@ -690,9 +690,8 @@ static int dwc_pcie_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_n { struct dwc_pcie_pmu *pcie_pmu; struct pci_dev *pdev; - int node; - cpumask_t mask; unsigned int target; + int node; pcie_pmu = hlist_entry_safe(cpuhp_node, struct dwc_pcie_pmu, cpuhp_node); /* Nothing to do if this CPU doesn't own the PMU */ @@ -702,10 +701,9 @@ static int dwc_pcie_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_n pcie_pmu->on_cpu = -1; pdev = pcie_pmu->pdev; node = dev_to_node(&pdev->dev); - 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_and_but(cpumask_of_node(node), cpu_online_mask, cpu); + if (target >= nr_cpu_ids) target = cpumask_any_but(cpu_online_mask, cpu); if (target >= nr_cpu_ids) {