drm/gma500: fix null pointer dereference in psb_intel_lvds_get_modes

In psb_intel_lvds_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: 89c78134cc54 ("gma500: Add Poulsbo support")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240709092011.3204970-1-make24@iscas.ac.cn

diff --git a/drivers/gpu/drm/gma500/psb_intel_lvds.c b/drivers/gpu/drm/gma500/psb_intel_lvds.c
index 8486de2..8d1be94 100644 (file)
--- a/drivers/gpu/drm/gma500/psb_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/psb_intel_lvds.c
@@ -504,6 +504,9 @@ static int psb_intel_lvds_get_modes(struct drm_connector *connector)
        if (mode_dev->panel_fixed_mode != NULL) {
                struct drm_display_mode *mode =
                    drm_mode_duplicate(dev, mode_dev->panel_fixed_mode);
+               if (!mode)
+                       return 0;
+
                drm_mode_probed_add(connector, mode);
                return 1;
        }