diff --git a/ChangeLog b/ChangeLog
index 8e81106af9..bc73b9b020 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Jul 20 14:21:38 2010  Narihiro Nakamura  <authorNari@gmail.com>
+
+	* gc.c: don't call after_gc_sweep() after when garbage_collect()
+	  was called, because rb_sweep_method_entry() free live unlinked
+	  method entries. [ruby-core:31169]
+
 Tue Jul 20 12:42:06 2010  URABE Shyouhei  <shyouhei@ruby-lang.org>
 
 	* ext/socket/raddrinfo.c (rb_getaddrinfo): according to my
diff --git a/gc.c b/gc.c
index 0c139400cf..db3dce55bf 100644
--- a/gc.c
+++ b/gc.c
@@ -2055,16 +2055,17 @@ gc_lazy_sweep(rb_objspace_t *objspace)
     GC_PROF_TIMER_START;
     GC_PROF_SWEEP_TIMER_START;
 
-    res = lazy_sweep(objspace);
-    if (res) {
-        GC_PROF_SWEEP_TIMER_STOP;
-        GC_PROF_SET_MALLOC_INFO;
-        GC_PROF_TIMER_STOP(Qfalse);
-        return res;
+    if (objspace->heap.sweep_slots) {
+        res = lazy_sweep(objspace);
+        if (res) {
+            GC_PROF_SWEEP_TIMER_STOP;
+            GC_PROF_SET_MALLOC_INFO;
+            GC_PROF_TIMER_STOP(Qfalse);
+            return res;
+        }
+        after_gc_sweep(objspace);
     }
 
-    after_gc_sweep(objspace);
-
     gc_marks(objspace);
 
     before_gc_sweep(objspace);