From 7ffd763439990f18f2045e6bb1f0937085ef6e6c Mon Sep 17 00:00:00 2001
From: Benjamin Valentin <benjamin.valentin@ml-pa.com>
Date: Sun, 15 Mar 2026 13:36:52 +0200
Subject: [PATCH] xf86: check return value of XF86_CRTC_CONFIG_PTR in
 xf86CompatOutput()

If privates[xf86CrtcConfigPrivateIndex].ptr is NULL, this will cause
a segfault.

Possible fix for https://gitlab.freedesktop.org/xorg/xserver/-/issues/1241

Signed-off-by: Benjamin Valentin <benjamin.valentin@ml-pa.com>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/835>
---
 include/xf86Crtc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/xf86Crtc.h b/include/xf86Crtc.h
index 1eeda5665d..bacafa6252 100644
--- a/include/xf86Crtc.h
+++ b/include/xf86Crtc.h
@@ -842,7 +842,7 @@ xf86CompatOutput(ScrnInfoPtr pScrn)
     if (xf86CrtcConfigPrivateIndex == -1)
         return NULL;
     config = XF86_CRTC_CONFIG_PTR(pScrn);
-    if (config->compat_output < 0)
+    if ((config == NULL) || (config->compat_output < 0))
         return NULL;
     return config->output[config->compat_output];
 }