6.6-stable review patch. If anyone has any objections, please let me know.
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From: Maíra Canal mcanal@igalia.com
commit 0b2ad4f6f2bec74a5287d96cb2325a5e11706f22 upstream.
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 However, this pointer is no longer valid because the previous process has already terminated, and all performance monitors associated with it have been destroyed and freed.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 Reviewed-by: Juan A. Suarez jasuarez@igalia.com Link: https://patchwork.freedesktop.org/patch/msgid/20241004123817.890016-2-mcanal... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/vc4/vc4_perfmon.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- 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_fi 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_f 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);