From: Joshua Aberback joshua.aberback@amd.com

[Why] The mechanism to backup and restore plane states doesn't maintain refcount, which can cause issues if the refcount of the plane changes in between backup and restore operations, such as memory leaks if the refcount was supposed to go down, or double frees / invalid memory accesses if the refcount was supposed to go up.

[How] Cache and re-apply current refcount when restoring plane states.

Cc: stable@vger.kernel.org Reviewed-by: Josip Pavic josip.pavic@amd.com Signed-off-by: Joshua Aberback joshua.aberback@amd.com Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com --- drivers/gpu/drm/amd/display/dc/core/dc.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c index 7872c6cabb14..0c1875d35a95 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c @@ -3141,7 +3141,10 @@ static void restore_planes_and_stream_state( return;

for (i = 0; i < status->plane_count; i++) { + /* refcount will always be valid, restore everything else */ + struct kref refcount = status->plane_states[i]->refcount; *status->plane_states[i] = scratch->plane_states[i]; + status->plane_states[i]->refcount = refcount; } *stream = scratch->stream_state; }