diff mbox series

cpufreq: mediatek: Fix potential deadlock problem in mtk_cpufreq_set_target

Message ID 20220510080136.11950-1-wanjiabing@vivo.com (mailing list archive)
State Superseded, archived
Headers show
Series cpufreq: mediatek: Fix potential deadlock problem in mtk_cpufreq_set_target | expand

Commit Message

Jiabing Wan May 10, 2022, 8:01 a.m. UTC
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")
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
---
 drivers/cpufreq/mediatek-cpufreq.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Viresh Kumar May 10, 2022, 8:12 a.m. UTC | #1
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 ??

> Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
> ---
>  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
Jiabing Wan May 10, 2022, 8:26 a.m. UTC | #2
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@vivo.com>
>> ---
>>   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
Viresh Kumar May 10, 2022, 8:50 a.m. UTC | #3
On 10-05-22, 16:26, Jiabing Wan wrote:
> 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...

Did you write this line by hand or generate it with Git ? There shouldn't be a
typo here.

> 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.

Yes, we need to release the lock.
Jiabing Wan May 10, 2022, 8:58 a.m. UTC | #4
On 2022/5/10 16:50, Viresh Kumar wrote:
> On 10-05-22, 16:26, Jiabing Wan wrote:
>> 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...
> Did you write this line by hand or generate it with Git ? There shouldn't be a
> typo here.

Yes, I write this line by hand.
There must be something wrong when copying the subject line.

Maybe I should find some tools in git to avoid it in the future.
>> 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.
> Yes, we need to release the lock.
OK, I'll fix it in v2.

Thanks,
Wan Jiabing
Viresh Kumar May 10, 2022, 9:09 a.m. UTC | #5
On 10-05-22, 16:58, Jiabing Wan wrote:
> Yes, I write this line by hand.
> There must be something wrong when copying the subject line.
> 
> Maybe I should find some tools in git to avoid it in the future.

Add this to ~/.gitconfig

[pretty]
	fixes = Fixes: %h (\"%s\")

And then just do:

$ git log --pretty=fixes c210063b40ac

It shall give you:

Fixes: c210063b40ac ("cpufreq: mediatek: Add opp notification support")
Fixes: 6a17b3876bc8 ("cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking()")
Fixes: ead858bd128d ("cpufreq: mediatek: Move voltage limits to platform data")
Fixes: f126fbadce92 ("cpufreq: mediatek: Unregister platform device on exit")
Fixes: a3b8d1b12c6b ("cpufreq: mediatek: Fix NULL pointer dereference in mediatek-cpufreq")
Fixes: ffa7bdf7f344 ("cpufreq: mediatek: Make sram regulator optional")

and other patches as we did git log.

OR

Else you could do something like this to just see one commit:

$ git show -s  --pretty=oneline --pretty=fixes c210063b40ac
diff mbox series

Patch

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);