drm/omap: handle error if scale coefs are not found

If get_scale_coef functions fail, they return NULL, but we never check
the return value and could do a NULL deref. This should not happen as we
ought to validate the amount of scaling already earlier, but to be safe,
add the necessary check.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180502091159.7071-3-tomi.valkeinen@ti.com
Reviewed-by: Benoit Parrot <bparrot@ti.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>

diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c
index 5e2e65e..b8fdb63 100644 (file)
--- a/drivers/gpu/drm/omapdrm/dss/dispc.c
+++ b/drivers/gpu/drm/omapdrm/dss/dispc.c
@@ -828,6 +828,12 @@ static void dispc_ovl_set_scale_coef(struct dispc_device *dispc,
        h_coef = dispc_ovl_get_scale_coef(fir_hinc, true);
        v_coef = dispc_ovl_get_scale_coef(fir_vinc, five_taps);
 
+       if (!h_coef || !v_coef) {
+               dev_err(&dispc->pdev->dev, "%s: failed to find scale coefs\n",
+                       __func__);
+               return;
+       }
+
        for (i = 0; i < 8; i++) {
                u32 h, hv;