[PATCH] drm/client: Do not destroy NULL modes

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

'modes' in drm_client_modeset_probe may fail to kcalloc.  If this
occurs, we jump to 'out', calling modes_destroy on it, which
dereferences it.  This may result in a NULL pointer dereference in the
error case.  Prevent that.

Fixes: 3039cc0c0653 ("drm/client: Make copies of modes")
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/drm_client_modeset.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index 262b1b8773c5..bb49b8361271 100644
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -930,7 +930,8 @@ int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
 	mutex_unlock(&client->modeset_mutex);
 out:
 	kfree(crtcs);
-	modes_destroy(dev, modes, connector_count);
+	if (modes)
+		modes_destroy(dev, modes, connector_count);
 	kfree(modes);
 	kfree(offsets);
 	kfree(enabled);
-- 
2.43.0