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 However, this pointer is no longer valid because the previous process has already terminated, and all performance monitors associated with it have been destroyed and freed.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);
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);
On 10/4/24 09:36, 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(-)
Applied to misc/kernel.git (drm-misc-fixes).
Best Regards, - Maíra
linux-stable-mirror@lists.linaro.org
-
Juan A. Suárez -
Maíra Canal