From patchwork Wed May 11 15:51:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 571681 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56D62C433EF for ; Wed, 11 May 2022 15:52:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343980AbiEKPwA (ORCPT ); Wed, 11 May 2022 11:52:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232122AbiEKPv7 (ORCPT ); Wed, 11 May 2022 11:51:59 -0400 Received: from cloudserver094114.home.pl (cloudserver094114.home.pl [79.96.170.134]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B65B263BDC; Wed, 11 May 2022 08:51:57 -0700 (PDT) Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 5.0.0) id d8280e60ce8cbe7d; Wed, 11 May 2022 17:51:55 +0200 Received: from kreacher.localnet (unknown [213.134.181.161]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id E7F4066C3E6; Wed, 11 May 2022 17:51:54 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM Cc: LKML , Viresh Kumar Subject: [PATCH v1 3/3] cpufreq: Rearrange locking in cpufreq_remove_dev() Date: Wed, 11 May 2022 17:51:39 +0200 Message-ID: <1836239.tdWV9SEqCh@kreacher> In-Reply-To: <5585781.DvuYhMxLoT@kreacher> References: <5585781.DvuYhMxLoT@kreacher> MIME-Version: 1.0 X-CLIENT-IP: 213.134.181.161 X-CLIENT-HOSTNAME: 213.134.181.161 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedvfedrgeehgdeltdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfjqffogffrnfdpggftiffpkfenuceurghilhhouhhtmecuudehtdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvvefufffkjghfggfgtgesthfuredttddtjeenucfhrhhomhepfdftrghfrggvlhculfdrucghhihsohgtkhhifdcuoehrjhifsehrjhifhihsohgtkhhirdhnvghtqeenucggtffrrghtthgvrhhnpedvffeuiedtgfdvtddugeeujedtffetteegfeekffdvfedttddtuefhgeefvdejhfenucfkphepvddufedrudefgedrudekuddrudeiudenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpedvudefrddufeegrddukedurdduiedupdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhnsggprhgtphhtthhopeefpdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepvhhirhgvshhhrdhkuhhmrghrsehlihhnrghrohdrohhrgh X-DCC--Metrics: v370.home.net.pl 1024; Body=3 Fuz1=3 Fuz2=3 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki Currently, cpufreq_remove_dev() invokes the ->exit() driver callback without holding the policy rwsem which is inconsistent with what happens if ->exit() is invoked directly from cpufreq_offline(). It also manipulates the real_cpus mask and removes the CPU device symlink without holding the policy rwsem, but cpufreq_offline() holds the rwsem around the modifications thereof. For consistency, modify cpufreq_remove_dev() to hold the policy rwsem until the ->exit() callback has been called (or it has been determined that it is not necessary to call it). Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) Index: linux-pm/drivers/cpufreq/cpufreq.c =================================================================== --- linux-pm.orig/drivers/cpufreq/cpufreq.c +++ linux-pm/drivers/cpufreq/cpufreq.c @@ -1659,19 +1659,26 @@ static void cpufreq_remove_dev(struct de if (!policy) return; + down_write(&policy->rwsem); + if (cpu_online(cpu)) - cpufreq_offline(cpu); + __cpufreq_offline(cpu, policy); cpumask_clear_cpu(cpu, policy->real_cpus); remove_cpu_dev_symlink(policy, dev); - if (cpumask_empty(policy->real_cpus)) { - /* We did light-weight exit earlier, do full tear down now */ - if (cpufreq_driver->offline) - cpufreq_driver->exit(policy); - - cpufreq_policy_free(policy); + if (!cpumask_empty(policy->real_cpus)) { + up_write(&policy->rwsem); + return; } + + /* We did light-weight exit earlier, do full tear down now */ + if (cpufreq_driver->offline) + cpufreq_driver->exit(policy); + + up_write(&policy->rwsem); + + cpufreq_policy_free(policy); } /**