1 files changed, 11 insertions, 0 deletions
diff --git a/ext/tk/tkutil.c b/ext/tk/tkutil.c
index b3e79430dd..aaa77b1aa8 100644
--- a/ext/tk/tkutil.c
+++ b/ext/tk/tkutil.c
@@ -9,6 +9,7 @@
 ************************************************/
 
 #include "ruby.h"
+#include "rubysig.h"
 #include "st.h"
 
 static VALUE cMethod;
@@ -1133,6 +1134,13 @@ cbsubst_scan_args(self, arg_key, val_ary)
     char *ptr;
     volatile VALUE dst = rb_ary_new2(len);
     volatile VALUE proc;
+    int thr_crit_bup;
+    VALUE old_gc;
+
+    thr_crit_bup = rb_thread_critical;
+    rb_thread_critical = Qtrue;
+
+    old_gc = rb_gc_disable();
 
     Data_Get_Struct(rb_const_get(self, ID_SUBST_INFO), 
 		    struct cbsubst_info, inf);
@@ -1161,6 +1169,9 @@ cbsubst_scan_args(self, arg_key, val_ary)
 	}
     }
 
+    if (old_gc == Qfalse) rb_gc_enable();
+    rb_thread_critical = thr_crit_bup;
+
     return dst;
 }