linux-kernel - [PATCH] drm/amdgpu/display: fix ref count leak when pm_runtime_get

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Message-Id: <20200614070530.56366-1-navid.emamdoost@gmail.com>
Date:   Sun, 14 Jun 2020 02:05:28 -0500
From:   Navid Emamdoost <navid.emamdoost@...il.com>
To:     Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, Lyude Paul <lyude@...hat.com>,
        Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>,
        José Roberto de Souza <jose.souza@...el.com>,
        Andrzej Pietrasiewicz <andrzej.p@...labora.com>,
        Navid Emamdoost <navid.emamdoost@...il.com>,
        amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Cc:     emamd001@....edu, wu000273@....edu, kjlu@....edu, smccaman@....edu
Subject: [PATCH] drm/amdgpu/display: fix ref count leak when pm_runtime_get_sync fails

The call to pm_runtime_get_sync increments the counter even in case of
failure, leading to incorrect ref count.
In case of failure, decrement the ref count before returning.

Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index f355d9a752d2..a1aec205435d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -716,8 +716,10 @@ amdgpu_connector_lvds_detect(struct drm_connector *connector, bool force)
 
 	if (!drm_kms_helper_is_poll_worker()) {
 		r = pm_runtime_get_sync(connector->dev->dev);
-		if (r < 0)
+		if (r < 0) {
+			pm_runtime_put_autosuspend(connector->dev->dev);
 			return connector_status_disconnected;
+		}
 	}
 
 	if (encoder) {
@@ -854,8 +856,10 @@ amdgpu_connector_vga_detect(struct drm_connector *connector, bool force)
 
 	if (!drm_kms_helper_is_poll_worker()) {
 		r = pm_runtime_get_sync(connector->dev->dev);
-		if (r < 0)
+		if (r < 0) {
+			pm_runtime_put_autosuspend(connector->dev->dev);
 			return connector_status_disconnected;
+		}
 	}
 
 	encoder = amdgpu_connector_best_single_encoder(connector);
@@ -977,8 +981,10 @@ amdgpu_connector_dvi_detect(struct drm_connector *connector, bool force)
 
 	if (!drm_kms_helper_is_poll_worker()) {
 		r = pm_runtime_get_sync(connector->dev->dev);
-		if (r < 0)
+		if (r < 0) {
+			pm_runtime_put_autosuspend(connector->dev->dev);
 			return connector_status_disconnected;
+		}
 	}
 
 	if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
@@ -1328,8 +1334,10 @@ amdgpu_connector_dp_detect(struct drm_connector *connector, bool force)
 
 	if (!drm_kms_helper_is_poll_worker()) {
 		r = pm_runtime_get_sync(connector->dev->dev);
-		if (r < 0)
+		if (r < 0) {
+			pm_runtime_put_autosuspend(connector->dev->dev);
 			return connector_status_disconnected;
+		}
 	}
 
 	if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
-- 
2.17.1