Messages in this thread | | | Subject | Re: [PATCH] drm/panfrost: fix reference leak in panfrost_job_hw_submit | From | Steven Price <> | Date | Fri, 27 Nov 2020 10:06:11 +0000 |
| |
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 <hulkci@huawei.com> > Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com> > --- > 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; > >
| |