LinuxLists.cc - [PATCH] drm/panfrost: fix ref count leak in panfrost_job_hw

2020-06-14 06:31:41

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

in panfrost_job_hw_submit, pm_runtime_get_sync is called which
increments the counter even in case of failure, leading to incorrect
ref count. In case of failure, decrement the ref count before returning.

Signed-off-by: Navid Emamdoost <[email protected]>
---
drivers/gpu/drm/panfrost/panfrost_job.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 7914b1570841..89ac84667eb1 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -147,11 +147,10 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)

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

if (WARN_ON(job_read(pfdev, JS_COMMAND_NEXT(js)))) {
- pm_runtime_put_sync_autosuspend(pfdev->dev);
- return;
+ goto out;
}

cfg = panfrost_mmu_as_get(pfdev, &job->file_priv->mmu);
@@ -184,6 +183,9 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
job, js, jc_head);

job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
+out:
+ pm_runtime_put_sync_autosuspend(pfdev->dev);
+ return;
}

static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
--
2.17.1

2020-06-14 11:33:35

by Markus Elfring

[permalink] [raw]

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

> in panfrost_job_hw_submit, …

* Can the term “reference count” become relevant also for this commit message
besides other possible adjustments?

* Would you like to add the tag “Fixes”?

…
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
…
> @@ -184,6 +183,9 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> job, js, jc_head);
>
> job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
> +out:
> + pm_runtime_put_sync_autosuspend(pfdev->dev);
> + return;
> }
…

Perhaps use the label “put_sync” instead?

Regards,
Markus

2020-06-14 11:33:37

by Markus Elfring

[permalink] [raw]

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

2020-06-14 11:33:39

by Markus Elfring

[permalink] [raw]

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

2020-07-07 02:32:23

by Alyssa Rosenzweig

[permalink] [raw]

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

Acked-by: Alyssa Rosenzweig <[email protected]>

On Sun, Jun 14, 2020 at 01:27:30AM -0500, Navid Emamdoost wrote:
> in panfrost_job_hw_submit, pm_runtime_get_sync is called which
> increments the counter even in case of failure, leading to incorrect
> ref count. In case of failure, decrement the ref count before returning.
>
> Signed-off-by: Navid Emamdoost <[email protected]>
> ---
> drivers/gpu/drm/panfrost/panfrost_job.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 7914b1570841..89ac84667eb1 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -147,11 +147,10 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>
> ret = pm_runtime_get_sync(pfdev->dev);
> if (ret < 0)
> - return;
> + goto out;
>
> if (WARN_ON(job_read(pfdev, JS_COMMAND_NEXT(js)))) {
> - pm_runtime_put_sync_autosuspend(pfdev->dev);
> - return;
> + goto out;
> }
>
> cfg = panfrost_mmu_as_get(pfdev, &job->file_priv->mmu);
> @@ -184,6 +183,9 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> job, js, jc_head);
>
> job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
> +out:
> + pm_runtime_put_sync_autosuspend(pfdev->dev);
> + return;
> }
>
> static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
> --
> 2.17.1
>

2020-07-09 15:48:51

by Rob Herring (Arm)

[permalink] [raw]

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

On Sun, Jun 14, 2020 at 12:27 AM Navid Emamdoost
<[email protected]> wrote:
>
> in panfrost_job_hw_submit, pm_runtime_get_sync is called which
> increments the counter even in case of failure, leading to incorrect
> ref count. In case of failure, decrement the ref count before returning.
>
> Signed-off-by: Navid Emamdoost <[email protected]>
> ---
> drivers/gpu/drm/panfrost/panfrost_job.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 7914b1570841..89ac84667eb1 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -147,11 +147,10 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>
> ret = pm_runtime_get_sync(pfdev->dev);
> if (ret < 0)
> - return;
> + goto out;

If the get failed, I don't think we want to do a put.

>
> if (WARN_ON(job_read(pfdev, JS_COMMAND_NEXT(js)))) {
> - pm_runtime_put_sync_autosuspend(pfdev->dev);
> - return;
> + goto out;
> }
>
> cfg = panfrost_mmu_as_get(pfdev, &job->file_priv->mmu);
> @@ -184,6 +183,9 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
> job, js, jc_head);
>
> job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);

So we start the job here and then...

> +out:
> + pm_runtime_put_sync_autosuspend(pfdev->dev);

...turn off clocks/power here. Typically, you'd be fine as autosuspend
has a delay by default, but userspace is free to change the delay to
0.

> + return;
> }
>
> static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
> --
> 2.17.1
>

2020-07-09 16:02:04

by Steven Price

[permalink] [raw]

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

On 09/07/2020 16:44, Rob Herring wrote:
> On Sun, Jun 14, 2020 at 12:27 AM Navid Emamdoost
> <[email protected]> wrote:
>>
>> in panfrost_job_hw_submit, pm_runtime_get_sync is called which
>> increments the counter even in case of failure, leading to incorrect
>> ref count. In case of failure, decrement the ref count before returning.
>>
>> Signed-off-by: Navid Emamdoost <[email protected]>
>> ---
>> drivers/gpu/drm/panfrost/panfrost_job.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
>> index 7914b1570841..89ac84667eb1 100644
>> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
>> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
>> @@ -147,11 +147,10 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>>
>> ret = pm_runtime_get_sync(pfdev->dev);
>> if (ret < 0)
>> - return;
>> + goto out;
>
> If the get failed, I don't think we want to do a put.

The pm_runtime_get_sync() does actually always increment the reference
(even when returning a failure), but actually I don't think we want it
here anyway, as I think I explained before[1].
[1]
https://lore.kernel.org/dri-devel/[email protected]
>
>>
>> if (WARN_ON(job_read(pfdev, JS_COMMAND_NEXT(js)))) {
>> - pm_runtime_put_sync_autosuspend(pfdev->dev);

This is a correct change - we don't want the put here. (Although this
should never happen).

>> - return;
>> + goto out;
>> }
>>
>> cfg = panfrost_mmu_as_get(pfdev, &job->file_priv->mmu);
>> @@ -184,6 +183,9 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>> job, js, jc_head);
>>
>> job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
>
> So we start the job here and then...
>
>> +out:
>> + pm_runtime_put_sync_autosuspend(pfdev->dev);
>
> ...turn off clocks/power here. Typically, you'd be fine as autosuspend
> has a delay by default, but userspace is free to change the delay to
> 0.
>
>> + return;

A return at the end of the function with no argument is pointless.

Steve

>> }
>>
>> static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
>> --
>> 2.17.1
>>