[PATCH 4.19 36/66] drm/nouveau: fix null pointer dereference in nouveau_connector_get_modes

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ma Ke <make24@iscas.ac.cn>

commit 80bec6825b19d95ccdfd3393cf8ec15ff2a749b4 upstream.

In nouveau_connector_get_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a possible NULL pointer
dereference on failure of drm_mode_duplicate(). Add a check to avoid npd.

Cc: stable@vger.kernel.org
Fixes: 6ee738610f41 ("drm/nouveau: Add DRM driver for NVIDIA GPUs")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240627074204.3023776-1-make24@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/nouveau/nouveau_connector.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -934,6 +934,9 @@ nouveau_connector_get_modes(struct drm_c
 		struct drm_display_mode *mode;
 
 		mode = drm_mode_duplicate(dev, nv_connector->native_mode);
+		if (!mode)
+			return 0;
+
 		drm_mode_probed_add(connector, mode);
 		ret = 1;
 	}