From dc8c5e3aaac1f0fb6027b5b560811e16f99dea4e Mon Sep 17 00:00:00 2001
From: Alan Coopersmith <alan.coopersmith@oracle.com>
Date: Sun, 29 Mar 2026 14:24:17 -0700
Subject: [PATCH] fb: quiet -Wanalyzer-out-of-bounds warnings in
 fbOverlayCopyWindow()

Reported in #1817:

xwayland-24.1.6/redhat-linux-build/../fb/fboverlay.c:230:13:
 warning[-Wanalyzer-out-of-bounds]: stack-based buffer over-read
xwayland-24.1.6/redhat-linux-build/../fb/fboverlay.c:233:9:
 warning[-Wanalyzer-out-of-bounds]: stack-based buffer over-read

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2162>
---
 fb/fboverlay.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fb/fboverlay.c b/fb/fboverlay.c
index d47a7c67b..4a5e899f6 100644
--- a/fb/fboverlay.c
+++ b/fb/fboverlay.c
@@ -26,6 +26,7 @@
 #include <dix-config.h>
 #endif
 
+#include <assert.h>
 #include <stdlib.h>
 
 #include "fb.h"
@@ -210,6 +211,7 @@ fbOverlayCopyWindow(WindowPtr pWin, DDXPointRec ptOldOrg, RegionPtr prgnSrc)
     /*
      * Compute the portion of each fb affected by this copy
      */
+    assert(pScrPriv->nlayers <= FB_OVERLAY_MAX);
     for (i = 0; i < pScrPriv->nlayers; i++) {
         RegionNull(&layerRgn[i]);
         RegionIntersect(&layerRgn[i], &rgnDst,