From 74565380aa1c342dc2fe3ac4de0fcf72c1698ceb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marco=20Trevisan=20=28Trevi=C3=B1o=29?= <mail@3v1n0.net>
Date: Thu, 19 Oct 2017 20:11:39 -0500
Subject: [PATCH] MetaPluginManager: don't try to deference a NULL pointer when
 processing events

This function might be called by components with invalid plugin manager
(as it might happen to MetaWindow when the compositor isn't initialized
properly), so we need to protect ourselves from crashes.

https://bugzilla.gnome.org/show_bug.cgi?id=789223
---
 src/compositor/meta-plugin-manager.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/compositor/meta-plugin-manager.c b/src/compositor/meta-plugin-manager.c
index 834f678dd..9f6e67273 100644
--- a/src/compositor/meta-plugin-manager.c
+++ b/src/compositor/meta-plugin-manager.c
@@ -153,10 +153,17 @@ meta_plugin_manager_event_simple (MetaPluginManager *plugin_mgr,
                                   MetaWindowActor   *actor,
                                   MetaPluginEffect   event)
 {
-  MetaPlugin *plugin = plugin_mgr->plugin;
-  MetaPluginClass *klass = META_PLUGIN_GET_CLASS (plugin);
-  MetaDisplay *display = plugin_mgr->compositor->display;
-  gboolean retval = FALSE;
+  MetaPlugin *plugin;
+  MetaPluginClass *klass;
+  MetaDisplay *display;
+  gboolean retval;
+
+  g_return_val_if_fail (plugin_mgr, FALSE);
+
+  plugin = plugin_mgr->plugin;
+  klass = META_PLUGIN_GET_CLASS (plugin);
+  display = plugin_mgr->compositor->display;
+  retval = FALSE;
 
   if (display->display_opening)
     return FALSE;