- Fixed bug #47341: Calling gc_collect_cycles() with zend.enable_gc=0 causes

segfault.

Zend/tests/gc_031.phpt

@@ -0,0 +1,11 @@
+--TEST--
+GC 031: gc_collect_roots() with GC turned off.
+--INI--
+zend.enable_gc=0
+--FILE--
+<?php
+gc_collect_cycles();
+echo "DONE\n";
+?>
+--EXPECTF--
+DONE

Zend/zend_gc.c

@@ -527,7 +527,7 @@ ZEND_API int gc_collect_cycles(TSRMLS_D)
 {
 	int count = 0;
 
-	if (GC_G(roots).next != &GC_G(roots)) {
+	if (GC_G(roots).next != &GC_G(roots) && GC_G(roots).next) {
 		zval_gc_info *p, *q, *orig_free_list, *orig_next_to_free;
 
 		if (GC_G(gc_active)) {