From patchwork Wed Apr 3 12:51:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dawei Li X-Patchwork-Id: 13616059 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 43755CD1288 for ; Wed, 3 Apr 2024 12:54:47 +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=A41ti/FA9vJ2GEplZDix82GiSe4odngAR1Y5NSedg+Y=; b=ETjhuxIQaTC0lw l7Xc3AMhCMDHGIZSoj32+I7tRlzRcoJeeQu45yJvXGBkS2AnMVpz0PHfJ6JSpNuK88cOXvBh2ShuN XHjrEScwmKHTz0GzoeDD0xZ+y/z47+9qm6+/0d7c/MlaUSauXB6ByBBMjPA1/JPYJ3zuihjet/1Bg 3XerxFnz/cYdV2s7be7oyn34tEhED3BsqVluNFN4/+w5DH4vzeItlIWBmNQOhHDdDH47c3CUfPmF7 cgpo8cKfISgozblicnSC+R6+weYnKEvyiolhISTdaIUH+GCKtZtbz/u9tLG9hQgD8/OX00J69kRLF rga72FjPsn+l3Tts9/6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs08R-0000000G2R7-1oDH; Wed, 03 Apr 2024 12:54:35 +0000 Received: from smtpbguseast3.qq.com ([54.243.244.52]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rs08N-0000000G285-3e3B for linux-arm-kernel@lists.infradead.org; Wed, 03 Apr 2024 12:54:33 +0000 X-QQ-mid: bizesmtpsz1t1712148785t9jh8zy X-QQ-Originating-IP: glNtj0eRp0IOBFLCOi1CaGqaaEumMkerNThHocu9b+k= Received: from localhost ( [112.0.147.175]) by bizesmtp.qq.com (ESMTP) with id ; Wed, 03 Apr 2024 20:53:04 +0800 (CST) X-QQ-SSF: 01400000000000704000000A0000000 X-QQ-FEAT: +ynUkgUhZJkR1+2Xpbw3pa6lG4d42cKOBYOKy4eBM/Jbqbkv0AiQwK85DK9n1 983cnBzJioQLx2jW5n10h586uD5pFDBsC+v12PpxJYaKBi3CSH/AmSm88+X9mOQQH8/QZ63 PG3ju17FiN2Dd4TWCF7X1iXJfg63o8upsKBrlHBlhEbSbLEySN06aN/oYGc5jgiBcG8X5Bp 1lABsa0QVpzkBNFCbrjCZcdBy7xoNDq1ADjdWQkMU0CNhITXi0yskRVq33PqVBthi6fTNSt IzpNnzIqNNQRwXPQN80AGwyXXnm3YBgOIxP8o71LF5W4AFOgcKSD/GXhC0ne4Zx83dF2qUs DVPirTGQv4Rbo7GV7MzZpG3r4bkNn+xF135c0YgkOHUZKhO9xWOsAz+OjtOg5jvd7rZuX1h qA68Tfvh8S+vNUKQNWDDAAbW7BaVf2NZ X-QQ-GoodBg: 2 X-BIZMAIL-ID: 17308809335922861107 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 10/10] perf/thunderx2: Avoid placing cpumask var on stack Date: Wed, 3 Apr 2024 20:51:09 +0800 Message-Id: <20240403125109.2054881-11-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_055432_519805_8C3FA9B6 X-CRM114-Status: GOOD ( 11.90 ) 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/thunderx2_pmu.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/perf/thunderx2_pmu.c b/drivers/perf/thunderx2_pmu.c index e16d10c763de..b3377b662ffc 100644 --- a/drivers/perf/thunderx2_pmu.c +++ b/drivers/perf/thunderx2_pmu.c @@ -932,9 +932,8 @@ static int tx2_uncore_pmu_online_cpu(unsigned int cpu, static int tx2_uncore_pmu_offline_cpu(unsigned int cpu, struct hlist_node *hpnode) { - int new_cpu; struct tx2_uncore_pmu *tx2_pmu; - struct cpumask cpu_online_mask_temp; + unsigned int new_cpu; tx2_pmu = hlist_entry_safe(hpnode, struct tx2_uncore_pmu, hpnode); @@ -945,11 +944,8 @@ static int tx2_uncore_pmu_offline_cpu(unsigned int cpu, if (tx2_pmu->hrtimer_callback) hrtimer_cancel(&tx2_pmu->hrtimer); - cpumask_copy(&cpu_online_mask_temp, cpu_online_mask); - cpumask_clear_cpu(cpu, &cpu_online_mask_temp); - new_cpu = cpumask_any_and( - cpumask_of_node(tx2_pmu->node), - &cpu_online_mask_temp); + new_cpu = cpumask_any_and_but(cpumask_of_node(tx2_pmu->node), + cpu_online_mask, cpu); tx2_pmu->cpu = new_cpu; if (new_cpu >= nr_cpu_ids)