linux-kernel - [PATCH v7 11/15] thermal: devfreq_cooling: work on a copy of device status

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 11 May 2020 12:19:08 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        dri-devel@...ts.freedesktop.org, linux-omap@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
        linux-imx@....com
Cc:     Dietmar.Eggemann@....com, cw00.choi@...sung.com,
        b.zolnierkie@...sung.com, rjw@...ysocki.net, sudeep.holla@....com,
        viresh.kumar@...aro.org, nm@...com, sboyd@...nel.org,
        rui.zhang@...el.com, amit.kucheria@...durent.com,
        daniel.lezcano@...aro.org, mingo@...hat.com, peterz@...radead.org,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        rostedt@...dmis.org, qperret@...gle.com, bsegall@...gle.com,
        mgorman@...e.de, shawnguo@...nel.org, s.hauer@...gutronix.de,
        festevam@...il.com, kernel@...gutronix.de, khilman@...nel.org,
        agross@...nel.org, bjorn.andersson@...aro.org, robh@...nel.org,
        matthias.bgg@...il.com, steven.price@....com,
        tomeu.vizoso@...labora.com, alyssa.rosenzweig@...labora.com,
        airlied@...ux.ie, daniel@...ll.ch, liviu.dudau@....com,
        lorenzo.pieralisi@....com, lukasz.luba@....com,
        patrick.bellasi@...bug.net, orjan.eide@....com,
        rdunlap@...radead.org, mka@...omium.org
Subject: [PATCH v7 11/15] thermal: devfreq_cooling: work on a copy of device status

Devfreq framework can change the device status in the background. To
mitigate this situation make a copy of the status structure and use it
for internal calculations.

Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
 drivers/thermal/devfreq_cooling.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
index 396f16bb6566..36ec6a48606c 100644
--- a/drivers/thermal/devfreq_cooling.c
+++ b/drivers/thermal/devfreq_cooling.c
@@ -348,14 +348,20 @@ static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;
 	struct devfreq *df = dfc->devfreq;
-	struct devfreq_dev_status *status = &df->last_status;
-	unsigned long freq = status->current_frequency;
+	struct devfreq_dev_status status;
 	unsigned long busy_time;
+	unsigned long freq;
 	s32 dyn_power;
 	u32 static_power;
 	s32 est_power;
 	int i;
 
+	mutex_lock(&df->lock);
+	status = df->last_status;
+	mutex_unlock(&df->lock);
+
+	freq = status.current_frequency;
+
 	if (dfc->power_ops->get_real_power) {
 		/* Scale for resource utilization */
 		est_power = power * dfc->res_util;
@@ -367,8 +373,8 @@ static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
 		dyn_power = dyn_power > 0 ? dyn_power : 0;
 
 		/* Scale dynamic power for utilization */
-		busy_time = status->busy_time ?: 1;
-		est_power = (dyn_power * status->total_time) / busy_time;
+		busy_time = status.busy_time ?: 1;
+		est_power = (dyn_power * status.total_time) / busy_time;
 	}
 
 	/*
-- 
2.17.1