From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH V2] devfreq: rk3399_dmc: Don't use OPP structures outside of RCU locks Date: Mon, 5 Dec 2016 08:53:52 +0530 Message-ID: Return-path: Received: from mail-pg0-f45.google.com ([74.125.83.45]:33335 "EHLO mail-pg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751120AbcLEDYB (ORCPT ); Sun, 4 Dec 2016 22:24:01 -0500 Received: by mail-pg0-f45.google.com with SMTP id 3so131430843pgd.0 for ; Sun, 04 Dec 2016 19:24:01 -0800 (PST) Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Rafael Wysocki , MyungJoo Ham , Kyungmin Park Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, Stephen Boyd , nm@ti.com, Vincent Guittot , Viresh Kumar The OPP structures are abused to the best here, without understanding how the OPP core and RCU locks work. In short, the OPP pointer saved in 'rk3399_dmcfreq' can become invalid under your nose, as the OPP core may free it. Fix various abuses around OPP structures and calls. Compile tested only. Reviewed-by: Chanwoo Choi Signed-off-by: Viresh Kumar --- V1->V2: - Added Reviewed-by from Chanwoo. - Fixed an issue reported by buildbot. drivers/devfreq/rk3399_dmc.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c index 5063ac1a5939..75333050cdea 100644 --- a/drivers/devfreq/rk3399_dmc.c +++ b/drivers/devfreq/rk3399_dmc.c @@ -80,7 +80,6 @@ struct rk3399_dmcfreq { struct regulator *vdd_center; unsigned long rate, target_rate; unsigned long volt, target_volt; - struct dev_pm_opp *curr_opp; }; static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq, @@ -102,9 +101,6 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq, target_rate = dev_pm_opp_get_freq(opp); target_volt = dev_pm_opp_get_voltage(opp); - dmcfreq->rate = dev_pm_opp_get_freq(dmcfreq->curr_opp); - dmcfreq->volt = dev_pm_opp_get_voltage(dmcfreq->curr_opp); - rcu_read_unlock(); if (dmcfreq->rate == target_rate) @@ -165,7 +161,9 @@ static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq, if (err) dev_err(dev, "Cannot to set vol %lu uV\n", target_volt); - dmcfreq->curr_opp = opp; + dmcfreq->rate = target_rate; + dmcfreq->volt = target_volt; + out: mutex_unlock(&dmcfreq->lock); return err; @@ -431,8 +429,9 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev) rcu_read_unlock(); return PTR_ERR(opp); } + data->rate = dev_pm_opp_get_freq(opp); + data->volt = dev_pm_opp_get_voltage(opp); rcu_read_unlock(); - data->curr_opp = opp; rk3399_devfreq_dmc_profile.initial_freq = data->rate; -- 2.7.1.410.g6faf27b