From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Viresh Kumar , Lukasz Luba , Eduardo Valentin Subject: [PATCH 4.9 006/125] thermal: cpu_cooling: Avoid accessing potentially freed structures Date: Tue, 25 Jul 2017 12:18:41 -0700 Message-Id: <20170725192014.616505458@linuxfoundation.org> In-Reply-To: <20170725192014.314851996@linuxfoundation.org> References: <20170725192014.314851996@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Viresh Kumar commit 289d72afddf83440117c35d864bf0c6309c1d011 upstream. After the lock is dropped, it is possible that the cpufreq_dev gets freed before we call get_level() and that can cause kernel to crash. Drop the lock after we are done using the structure. Fixes: 02373d7c69b4 ("thermal: cpu_cooling: fix lockdep problems in cpu_cooling") Signed-off-by: Viresh Kumar Reviewed-by: Lukasz Luba Tested-by: Lukasz Luba Signed-off-by: Eduardo Valentin Signed-off-by: Greg Kroah-Hartman --- drivers/thermal/cpu_cooling.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/thermal/cpu_cooling.c +++ b/drivers/thermal/cpu_cooling.c @@ -191,8 +191,10 @@ unsigned long cpufreq_cooling_get_level( mutex_lock(&cooling_list_lock); list_for_each_entry(cpufreq_dev, &cpufreq_dev_list, node) { if (cpumask_test_cpu(cpu, &cpufreq_dev->allowed_cpus)) { + unsigned long level = get_level(cpufreq_dev, freq); + mutex_unlock(&cooling_list_lock); - return get_level(cpufreq_dev, freq); + return level; } } mutex_unlock(&cooling_list_lock);