From 6a5e47c57d16de8b6a6a2636f3cbad1aebec32e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <mdaenzer@redhat.com>
Date: Mon, 27 Jan 2020 17:47:10 +0100
Subject: [PATCH xserver] xfree86/modes: Bail from xf86RotateRedisplay if
 pScreen->root is NULL
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Avoids a crash in xf86RotatePrepare -> DamageRegister during
CreateScreenResources if rotation or another transform is configured for
any connected RandR output in xorg.conf. The generic rotation/transform
code generally can't work without the root window currently.

Closes: https://gitlab.freedesktop.org/xorg/xserver/issues/969
Fixes: 094f42cdfe5d "xfree86/modes: Call xf86RotateRedisplay from
                     xf86CrtcRotate"
Acked-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Michel Dänzer <mdaenzer@redhat.com>
---
 hw/xfree86/modes/xf86Rotate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/xfree86/modes/xf86Rotate.c b/hw/xfree86/modes/xf86Rotate.c
index 05944cfcb..5415ed97c 100644
--- a/hw/xfree86/modes/xf86Rotate.c
+++ b/hw/xfree86/modes/xf86Rotate.c
@@ -176,7 +176,7 @@ xf86RotateRedisplay(ScreenPtr pScreen)
     DamagePtr damage = xf86_config->rotation_damage;
     RegionPtr region;
 
-    if (!damage)
+    if (!damage || !pScreen->root)
         return FALSE;
     xf86RotatePrepare(pScreen);
     region = DamageRegion(damage);
-- 
2.24.1