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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rafael Wysocki <rjw@rjwysocki.net>,
	Javi Merino <javi.merino@kernel.org>,
	Zhang Rui <rui.zhang@intel.com>,
	Eduardo Valentin <edubezval@gmail.com>,
	Amit Daniel Kachhap <amit.kachhap@gmail.com>,
	Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"4 . 2+" <stable@vger.kernel.org>
Subject: [PATCH 01/17] thermal: cpu_cooling: Avoid accessing potentially freed structures
Date: Thu, 16 Mar 2017 10:59:36 +0530	[thread overview]
Message-ID: <be952dc502195304ddecfe4eefa7043eb71d0c6b.1489639999.git.viresh.kumar@linaro.org> (raw)
In-Reply-To: <cover.1489639999.git.viresh.kumar@linaro.org>

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.

Cc: 4.2+ <stable@vger.kernel.org>
Fixes: 02373d7c69b4 ("thermal: cpu_cooling: fix lockdep problems in cpu_cooling")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/thermal/cpu_cooling.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index c2525b585487..6fd258d62e47 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -155,8 +155,10 @@ unsigned long cpufreq_cooling_get_level(unsigned int cpu, unsigned int freq)
 	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);
-- 
2.7.1.410.g6faf27b

  reply	other threads:[~2017-03-16  5:30 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-16  5:26 [PATCH 00/17] thermal: cpu_cooling: improve interaction with cpufreq core Viresh Kumar
2017-03-16  5:29 ` Viresh Kumar [this message]
2017-03-16  5:29 ` [PATCH 02/17] thermal: cpu_cooling: rearrange globals Viresh Kumar
2017-03-16  5:29 ` [PATCH 03/17] thermal: cpu_cooling: Replace cpufreq_device with cpufreq_dev Viresh Kumar
2017-04-11 17:33   ` Eduardo Valentin
2017-04-12  6:16     ` Viresh Kumar
2017-03-16  5:29 ` [PATCH 04/17] thermal: cpu_cooling: replace cool_dev with cdev Viresh Kumar
2017-04-11 17:35   ` Eduardo Valentin
2017-03-16  5:29 ` [PATCH 05/17] thermal: cpu_cooling: remove cpufreq_cooling_get_level() Viresh Kumar
2017-04-11 17:43   ` Eduardo Valentin
2017-04-12  6:25     ` Viresh Kumar
2017-03-16  5:29 ` [PATCH 06/17] thermal: cpu_cooling: get rid of a variable in cpufreq_set_cur_state() Viresh Kumar
2017-03-16  5:29 ` [PATCH 07/17] thermal: cpu_cooling: use cpufreq_policy to register cooling device Viresh Kumar
2017-03-16  5:29 ` [PATCH 08/17] cpufreq: create cpufreq_table_count_valid_entries() Viresh Kumar
2017-03-16  5:29 ` [PATCH 09/17] thermal: cpu_cooling: store cpufreq policy Viresh Kumar
2017-03-16  5:29 ` [PATCH 10/17] thermal: cpu_cooling: OPPs are registered for all CPUs Viresh Kumar
2017-03-16  5:29 ` [PATCH 11/17] thermal: cpu_cooling: get rid of 'allowed_cpus' Viresh Kumar
2017-03-16  5:29 ` [PATCH 12/17] thermal: cpu_cooling: merge frequency and power tables Viresh Kumar
2017-03-16  5:29 ` [PATCH 13/17] thermal: cpu_cooling: create structure for idle time stats Viresh Kumar
2017-03-16  5:29 ` [PATCH 14/17] thermal: cpu_cooling: get_level() can't fail Viresh Kumar
2017-03-16  5:29 ` [PATCH 15/17] thermal: cpu_cooling: don't store cpu_dev in cpufreq_dev Viresh Kumar
2017-03-16  5:29 ` [PATCH 16/17] thermal: cpu_cooling: 'freq' can't be zero in cpufreq_state2power() Viresh Kumar
2017-03-16  5:29 ` [PATCH 17/17] thermal: cpu_cooling: Rearrange struct cpufreq_cooling_device Viresh Kumar
2017-04-11  6:02 ` [PATCH 00/17] thermal: cpu_cooling: improve interaction with cpufreq core Viresh Kumar

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