[PATCH] fix: drm/amd/display: detect_link_and_local_sink: DP alt mode timeout path leaks prev_sink reference

[WenTao Liang]

prev_sink is unconditionally retained via dc_sink_retain at function
  entry, but the DP alt mode timeout path inside SIGNAL_TYPE_DISPLAY_PORT
  returns false without releasing prev_sink. All other return paths in the
  function correctly call dc_sink_release(prev_sink), making this the only
  missing cleanup.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 54618888d1ea ("drm/amd/display: break down dc_link.c")
Signed-off-by: WenTao Liang <vulab@xxxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/dc/link/link_detection.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/link_detection.c b/drivers/gpu/drm/amd/display/dc/link/link_detection.c
index 794dd6a95918..03bb210ebab8 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_detection.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_detection.c
@@ -1069,8 +1069,11 @@ static bool detect_link_and_local_sink(struct dc_link *link,
 			    link->link_enc->features.flags.bits.DP_IS_USB_C == 1) {
 
 				/* if alt mode times out, return false */
-				if (!wait_for_entering_dp_alt_mode(link))
+				if (!wait_for_entering_dp_alt_mode(link)) {
+					if (prev_sink)
+						dc_sink_release(prev_sink);
 					return false;
+				}
 			}
 
 			if (!detect_dp(link, &sink_caps, reason)) {
-- 
2.39.5 (Apple Git-154)