2020-11-27 09:45:47

by Qinglang Miao

Subject: [PATCH] drm/panfrost: fix reference leak in panfrost_job_hw_submit

pm_runtime_get_sync will increment pm usage counter even it
failed. Forgetting to putting operation will result in a
reference leak here.

A new function pm_runtime_resume_and_get is introduced in
[0] to keep usage counter balanced. So We fix the reference
leak by replacing it with new funtion.

[0] dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")

Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Qinglang Miao <[email protected]>
---
drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 30e7b7196..04cf3bb67 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -147,7 +147,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)

panfrost_devfreq_record_busy(&pfdev->pfdevfreq);

- ret = pm_runtime_get_sync(pfdev->dev);
+ ret = pm_runtime_resume_and_get(pfdev->dev);
if (ret < 0)
return;

--
2.23.0

2020-11-27 10:10:41

by Steven Price

Subject: Re: [PATCH] drm/panfrost: fix reference leak in panfrost_job_hw_submit

On 27/11/2020 09:44, Qinglang Miao wrote:
> pm_runtime_get_sync will increment pm usage counter even it
> failed. Forgetting to putting operation will result in a
> reference leak here.
>
> A new function pm_runtime_resume_and_get is introduced in
> [0] to keep usage counter balanced. So We fix the reference
> leak by replacing it with new funtion.
>
> [0] dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
>
> Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Qinglang Miao <[email protected]>
> ---
> drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 30e7b7196..04cf3bb67 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -147,7 +147,7 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>
> panfrost_devfreq_record_busy(&pfdev->pfdevfreq);
>
> - ret = pm_runtime_get_sync(pfdev->dev);
> + ret = pm_runtime_resume_and_get(pfdev->dev);

Sorry, but in this case this change isn't correct.
panfrost_job_hw_submit() is expected to be unbalanced (the PM reference
count is expected to be incremented on return).

In the case where pm_runtime_get_sync() fails, the job will eventually
timeout, and there's a corresponding pm_runtime_put_noidle() in
panfrost_reset().

Potentially this could be handled better (e.g. without waiting for the
timeout to occur), but equally this isn't something we expect to happen
in normal operation).

Steve

> if (ret < 0)
> return;
>
>

2020-11-30 12:29:05

by Qinglang Miao

Subject: Re: [PATCH] drm/panfrost: fix reference leak in panfrost_job_hw_submit

在 2020/11/27 18:06, Steven Price 写道:
> On 27/11/2020 09:44, Qinglang Miao wrote:
>> pm_runtime_get_sync will increment pm usage counter even it
>> failed. Forgetting to putting operation will result in a
>> reference leak here.
>>
>> A new function pm_runtime_resume_and_get is introduced in
>> [0] to keep usage counter balanced. So We fix the reference
>> leak by replacing it with new funtion.
>>
>> [0] dd8088d5a896 ("PM: runtime: Add  pm_runtime_resume_and_get to deal
>> with usage counter")
>>
>> Fixes: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
>> Reported-by: Hulk Robot <[email protected]>
>> Signed-off-by: Qinglang Miao <[email protected]>
>> ---
>>   drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c
>> b/drivers/gpu/drm/panfrost/panfrost_job.c
>> index 30e7b7196..04cf3bb67 100644
>> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
>> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
>> @@ -147,7 +147,7 @@ static void panfrost_job_hw_submit(struct
>> panfrost_job *job, int js)
>>       panfrost_devfreq_record_busy(&pfdev->pfdevfreq);
>> -    ret = pm_runtime_get_sync(pfdev->dev);
>> +    ret = pm_runtime_resume_and_get(pfdev->dev);
>
> Sorry, but in this case this change isn't correct.
> panfrost_job_hw_submit() is expected to be unbalanced (the PM reference
> count is expected to be incremented on return).
>
> In the case where pm_runtime_get_sync() fails, the job will eventually
> timeout, and there's a corresponding pm_runtime_put_noidle() in
> panfrost_reset().
>
> Potentially this could be handled better (e.g. without waiting for the
> timeout to occur), but equally this isn't something we expect to happen
> in normal operation).
>
> Steve
Sorry, I didn't notice the pm_runtime_put_noidle() in
panfrost_job_timedout() before.

Thanks for your reply.
>
>>       if (ret < 0)
>>           return;
>>
>
> .