From f327285ab3c5fcf60659cdb100b640f538b447ba Mon Sep 17 00:00:00 2001
From: Ruslan Kabalin <r.kabalin@lancaster.ac.uk>
Date: Wed, 31 Jul 2013 09:46:07 +0100
Subject: [PATCH] MDL-40947: Fix segmentation fault issue in get_fast_modinfo.

---
 lib/modinfolib.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/modinfolib.php b/lib/modinfolib.php
index 19b12c330c6..d48504ec640 100644
--- a/lib/modinfolib.php
+++ b/lib/modinfolib.php
@@ -1414,8 +1414,10 @@ function get_fast_modinfo($courseorid, $userid = 0, $resetonly = false) {
     if (count($cache) > MAX_MODINFO_CACHE_SIZE) {
         reset($cache);
         $key = key($cache);
-        unset($cache[$key]->instances);
-        unset($cache[$key]->cms);
+        // Unsetting static variable in PHP is percular, it removes the reference,
+        // but data remain in memory. Prior to unsetting, the varable needs to be
+        // set to empty to remove its remains from memory.
+        $cache[$key] = '';
         unset($cache[$key]);
     }