From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:59086 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751965AbeFXPb2 (ORCPT ); Sun, 24 Jun 2018 11:31:28 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kevin Wangtao , Viresh Kumar , "Rafael J. Wysocki" Subject: [PATCH 4.14 39/52] cpufreq: Fix new policy initialization during limits updates via sysfs Date: Sun, 24 Jun 2018 23:21:32 +0800 Message-Id: <20180624142746.780465691@linuxfoundation.org> In-Reply-To: <20180624142744.234164867@linuxfoundation.org> References: <20180624142744.234164867@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tao Wang commit c7d1f119c48f64bebf0fa1e326af577c6152fe30 upstream. If the policy limits are updated via cpufreq_update_policy() and subsequently via sysfs, the limits stored in user_policy may be set incorrectly. For example, if both min and max are set via sysfs to the maximum available frequency, user_policy.min and user_policy.max will also be the maximum. If a policy notifier triggered by cpufreq_update_policy() lowers both the min and the max at this point, that change is not reflected by the user_policy limits, so if the max is updated again via sysfs to the same lower value, then user_policy.max will be lower than user_policy.min which shouldn't happen. In particular, if one of the policy CPUs is then taken offline and back online, cpufreq_set_policy() will fail for it due to a failing limits check. To prevent that from happening, initialize the min and max fields of the new_policy object to the ones stored in user_policy that were previously set via sysfs. Signed-off-by: Kevin Wangtao Acked-by: Viresh Kumar [ rjw: Subject & changelog ] Cc: All applicable Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/cpufreq.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -693,6 +693,8 @@ static ssize_t store_##file_name \ struct cpufreq_policy new_policy; \ \ memcpy(&new_policy, policy, sizeof(*policy)); \ + new_policy.min = policy->user_policy.min; \ + new_policy.max = policy->user_policy.max; \ \ ret = sscanf(buf, "%u", &new_policy.object); \ if (ret != 1) \