diff mbox series

[2/2] drm/vc4: Stop the active perfmon before being destroyed

Message ID 20241004123817.890016-2-mcanal@igalia.com (mailing list archive)
State New
Headers show
Series [1/2] drm/vc4: Use `vc4_perfmon_find()` | expand

Commit Message

Maíra Canal Oct. 4, 2024, 12:36 p.m. UTC
Upon closing the file descriptor, the active performance monitor is not
stopped. Although all perfmons are destroyed in `vc4_perfmon_close_file()`,
the active performance monitor's pointer (`vc4->active_perfmon`) is still
retained.

If we open a new file descriptor and submit a few jobs with performance
monitors, the driver will attempt to stop the active performance monitor
using the stale pointer in `vc4->active_perfmon`. However, this pointer
is no longer valid because the previous process has already terminated,
and all performance monitors associated with it have been destroyed and
freed.

To fix this, when the active performance monitor belongs to a given
process, explicitly stop it before destroying and freeing it.

Cc: <stable@vger.kernel.org> # v4.17+
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Juan A. Suarez Romero <jasuarez@igalia.com>
Fixes: 65101d8c9108 ("drm/vc4: Expose performance counters to userspace")
Signed-off-by: Maíra Canal <mcanal@igalia.com>
---
 drivers/gpu/drm/vc4/vc4_perfmon.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Juan A." Suárez Oct. 4, 2024, 4:25 p.m. UTC | #1
Worth to mention we got this issue happened also for v3d (a fix was
already submitted).


Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>


On Fri, 2024-10-04 at 09:36 -0300, Maíra Canal wrote:
> Upon closing the file descriptor, the active performance monitor is
> not
> stopped. Although all perfmons are destroyed in
> `vc4_perfmon_close_file()`,
> the active performance monitor's pointer (`vc4->active_perfmon`) is
> still
> retained.
> 
> If we open a new file descriptor and submit a few jobs with
> performance
> monitors, the driver will attempt to stop the active performance
> monitor
> using the stale pointer in `vc4->active_perfmon`. However, this
> pointer
> is no longer valid because the previous process has already
> terminated,
> and all performance monitors associated with it have been destroyed
> and
> freed.
> 
> To fix this, when the active performance monitor belongs to a given
> process, explicitly stop it before destroying and freeing it.
> 
> Cc: <stable@vger.kernel.org> # v4.17+
> Cc: Boris Brezillon <bbrezillon@kernel.org>
> Cc: Juan A. Suarez Romero <jasuarez@igalia.com>
> Fixes: 65101d8c9108 ("drm/vc4: Expose performance counters to
> userspace")
> Signed-off-by: Maíra Canal <mcanal@igalia.com>
> ---
>  drivers/gpu/drm/vc4/vc4_perfmon.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_perfmon.c
> b/drivers/gpu/drm/vc4/vc4_perfmon.c
> index f2e56d0f6298..f1342f917cf7 100644
> --- a/drivers/gpu/drm/vc4/vc4_perfmon.c
> +++ b/drivers/gpu/drm/vc4/vc4_perfmon.c
> @@ -116,6 +116,11 @@ void vc4_perfmon_open_file(struct vc4_file
> *vc4file)
>  static int vc4_perfmon_idr_del(int id, void *elem, void *data)
>  {
>  	struct vc4_perfmon *perfmon = elem;
> +	struct vc4_dev *vc4 = (struct vc4_dev *)data;
> +
> +	/* If the active perfmon is being destroyed, stop it first
> */
> +	if (perfmon == vc4->active_perfmon)
> +		vc4_perfmon_stop(vc4, perfmon, false);
>  
>  	vc4_perfmon_put(perfmon);
>  
> @@ -130,7 +135,7 @@ void vc4_perfmon_close_file(struct vc4_file
> *vc4file)
>  		return;
>  
>  	mutex_lock(&vc4file->perfmon.lock);
> -	idr_for_each(&vc4file->perfmon.idr, vc4_perfmon_idr_del,
> NULL);
> +	idr_for_each(&vc4file->perfmon.idr, vc4_perfmon_idr_del,
> vc4);
>  	idr_destroy(&vc4file->perfmon.idr);
>  	mutex_unlock(&vc4file->perfmon.lock);
>  	mutex_destroy(&vc4file->perfmon.lock);
diff mbox series

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_perfmon.c b/drivers/gpu/drm/vc4/vc4_perfmon.c
index f2e56d0f6298..f1342f917cf7 100644
--- a/drivers/gpu/drm/vc4/vc4_perfmon.c
+++ b/drivers/gpu/drm/vc4/vc4_perfmon.c
@@ -116,6 +116,11 @@  void vc4_perfmon_open_file(struct vc4_file *vc4file)
 static int vc4_perfmon_idr_del(int id, void *elem, void *data)
 {
 	struct vc4_perfmon *perfmon = elem;
+	struct vc4_dev *vc4 = (struct vc4_dev *)data;
+
+	/* If the active perfmon is being destroyed, stop it first */
+	if (perfmon == vc4->active_perfmon)
+		vc4_perfmon_stop(vc4, perfmon, false);
 
 	vc4_perfmon_put(perfmon);
 
@@ -130,7 +135,7 @@  void vc4_perfmon_close_file(struct vc4_file *vc4file)
 		return;
 
 	mutex_lock(&vc4file->perfmon.lock);
-	idr_for_each(&vc4file->perfmon.idr, vc4_perfmon_idr_del, NULL);
+	idr_for_each(&vc4file->perfmon.idr, vc4_perfmon_idr_del, vc4);
 	idr_destroy(&vc4file->perfmon.idr);
 	mutex_unlock(&vc4file->perfmon.lock);
 	mutex_destroy(&vc4file->perfmon.lock);