drm/panel: fix a possible null pointer dereference

[ Upstream commit 924e5814d1f84e6fa5cb19c6eceb69f066225229 ]

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

Signed-off-by: Ma Ke <make_ruc2021@163.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231007033105.3997998-1-make_ruc2021@163.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231007033105.3997998-1-make_ruc2021@163.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/panel/panel-arm-versatile.c b/drivers/gpu/drm/panel/panel-arm-versatile.c
index abb0788..503ecea 100644 (file)
--- a/drivers/gpu/drm/panel/panel-arm-versatile.c
+++ b/drivers/gpu/drm/panel/panel-arm-versatile.c
@@ -267,6 +267,8 @@ static int versatile_panel_get_modes(struct drm_panel *panel,
        connector->display_info.bus_flags = vpanel->panel_type->bus_flags;
 
        mode = drm_mode_duplicate(connector->dev, &vpanel->panel_type->mode);
+       if (!mode)
+               return -ENOMEM;
        drm_mode_set_name(mode);
        mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;