Hi MyungJoo,

On Mon, Dec 5, 2016 at 4:23 AM, Viresh Kumar viresh.kumar@linaro.org wrote:

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 cw00.choi@samsung.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org

---

V1->V2:

• Added Reviewed-by from Chanwoo.
• Fixed an issue reported by buildbot.

I think this along with https://patchwork.kernel.org/patch/9455789/ and https://patchwork.kernel.org/patch/9455757/ should go into 4.10-rc1.

Are you going to send a pull request for this before the merge window or do you want me to apply them directly?

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;
  
  

--

Thanks, Rafael