[PATCH RESEND] drm/client: fix null pointer dereference in drm_client_modeset_probe

[Ma Ke]

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

Fixes: cf13909aee05 ("drm/fb-helper: Move out modeset config code")
Signed-off-by: Ma Ke <mak...@iscas.ac.cn>
---
 drivers/gpu/drm/drm_client_modeset.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_client_modeset.c 
b/drivers/gpu/drm/drm_client_modeset.c
index 31af5cf37a09..bbe21522dc6a 100644
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -880,6 +880,8 @@ int drm_client_modeset_probe(struct drm_client_dev *client, 
unsigned int width,
 
                        kfree(modeset->mode);
                        modeset->mode = drm_mode_duplicate(dev, mode);
+                       if (!modeset->mode)
+                               continue;
                        drm_connector_get(connector);
                        modeset->connectors[modeset->num_connectors++] = 
connector;
                        modeset->x = offset->x;
-- 
2.25.1