From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juri Lelli Subject: [RFC PATCH 13/19] cpufreq: fix locking of policy->rwsem in cpufreq_offline_prepare Date: Mon, 11 Jan 2016 17:35:54 +0000 Message-ID: <1452533760-13787-14-git-send-email-juri.lelli@arm.com> References: <1452533760-13787-1-git-send-email-juri.lelli@arm.com> Return-path: Received: from foss.arm.com ([217.140.101.70]:57278 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761184AbcAKRhi (ORCPT ); Mon, 11 Jan 2016 12:37:38 -0500 In-Reply-To: <1452533760-13787-1-git-send-email-juri.lelli@arm.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, peterz@infradead.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, mturquette@baylibre.com, steve.muckle@linaro.org, vincent.guittot@linaro.org, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com There are paths in cpufreq_offline_prepare where policy is used, but its rwsem is not held. Fix it. Cc: "Rafael J. Wysocki" Cc: Viresh Kumar Signed-off-by: Juri Lelli --- drivers/cpufreq/cpufreq.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 2c7cc6c73..91158b0 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1332,13 +1332,13 @@ static void cpufreq_offline_prepare(unsigned int cpu) return; } + down_write(&policy->rwsem); if (has_target()) { int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); if (ret) pr_err("%s: Failed to stop governor\n", __func__); } - down_write(&policy->rwsem); cpumask_clear_cpu(cpu, policy->cpus); if (policy_is_inactive(policy)) { @@ -1356,12 +1356,16 @@ static void cpufreq_offline_prepare(unsigned int cpu) /* Start governor again for active policy */ if (!policy_is_inactive(policy)) { if (has_target()) { - int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); + int ret; + + down_write(&policy->rwsem); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); if (!ret) ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); if (ret) pr_err("%s: Failed to start governor\n", __func__); + up_write(&policy->rwsem); } } else if (cpufreq_driver->stop_cpu) { cpufreq_driver->stop_cpu(policy); -- 2.2.2