Re: [PATCH] cpufreq: mediatek: Fix potential deadlock problem in mtk_cpufreq_set_target

[Jiabing Wan]

Hi, Viresh Kumar

On 2022/5/10 16:12, Viresh Kumar wrote:
> On 10-05-22, 16:01, Wan Jiabing wrote:
> > Fix following coccichek error:
> > ./drivers/cpufreq/mediatek-cpufreq.c:199:2-8: preceding lock on line
> > ./drivers/cpufreq/mediatek-cpufreq.c:208:2-8: preceding lock on line
> >
> > mutex_lock is acquired but not released before return.
> > Use 'goto out' to help releasing the mutex_lock.
> >
> > Fixes: c210063b40ac ("cupful: mediatek: Add opp notification support")
> cupful ??

Sorry for the typo...

By the way, is this patch correct?

I am not sure whether it should return with the mutex_lock.
But IMO, it should release the lock before return.

If correct, I'll fix this typo in v2.

Thanks,

Wan Jiabing
> > Signed-off-by: Wan Jiabing <wanjiabing@xxxxxxxx>
> > ---
> >   drivers/cpufreq/mediatek-cpufreq.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> > index 75bf21ddf61f..4c6d53c99d79 100644
> > --- a/drivers/cpufreq/mediatek-cpufreq.c
> > +++ b/drivers/cpufreq/mediatek-cpufreq.c
> > @@ -196,7 +196,8 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> >   
> >   	if (pre_vproc < 0) {
> >   		dev_err(cpu_dev, "invalid Vproc value: %d\n", pre_vproc);
> > -		return pre_vproc;
> > +		ret = pre_vproc;
> > +		goto out;
> >   	}
> >   
> >   	freq_hz = freq_table[index].frequency * 1000;
> > @@ -205,7 +206,8 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> >   	if (IS_ERR(opp)) {
> >   		dev_err(cpu_dev, "cpu%d: failed to find OPP for %ld\n",
> >   			policy->cpu, freq_hz);
> > -		return PTR_ERR(opp);
> > +		ret = PTR_ERR(opp);
> > +		goto out;
> >   	}
> >   	vproc = dev_pm_opp_get_voltage(opp);
> >   	dev_pm_opp_put(opp);
> > --
> > 2.35.1