diff --git a/core/strings/strings-tests.factor b/core/strings/strings-tests.factor
index c971287ef6..3ae7b92a5f 100755
--- a/core/strings/strings-tests.factor
+++ b/core/strings/strings-tests.factor
@@ -1,5 +1,6 @@
-USING: continuations kernel math namespaces strings sbufs
-tools.test sequences vectors arrays ;
+USING: continuations kernel math namespaces strings
+strings.private sbufs tools.test sequences vectors arrays memory
+prettyprint io.streams.null ;
 IN: strings.tests
 
 [ CHAR: b ] [ 1 >bignum "abc" nth ] unit-test
@@ -90,3 +91,28 @@ unit-test
     "\udeadbe" clone
     CHAR: \u123456 over clone set-first
 ] unit-test
+
+! Regressions
+[ ] [
+    [
+        4 [
+            100 [ drop "obdurak" ] map
+            gc
+            dup [
+                1234 0 rot set-string-nth
+            ] each
+            1000 [
+                1000 f <array> drop
+            ] times
+            .
+        ] times
+    ] with-null-stream
+] unit-test
+
+[ t ] [
+    10000 [
+        drop
+        300 100 CHAR: \u123456
+        [ <string> clone resize-string first ] keep =
+    ] all?
+] unit-test
diff --git a/vm/Config.unix b/vm/Config.unix
index 390a719c77..7817a36e3b 100644
--- a/vm/Config.unix
+++ b/vm/Config.unix
@@ -1,6 +1,4 @@
-#ifndef DEBUG
-    CFLAGS += -fomit-frame-pointer
-#endif
+CFLAGS = -fomit-frame-pointer
 
 EXE_SUFFIX =
 DLL_PREFIX = lib
diff --git a/vm/types.c b/vm/types.c
index f88c3ef3cb..d9fd152c97 100755
--- a/vm/types.c
+++ b/vm/types.c
@@ -50,6 +50,7 @@ F_WORD *allot_word(CELL vocab, CELL name)
 	word->counter = tag_fixnum(0);
 	word->compiledp = F;
 	word->profiling = NULL;
+	word->code = NULL;
 
 	REGISTER_UNTAGGED(word);
 	default_word_code(word,true);
@@ -108,8 +109,11 @@ F_ARRAY *allot_array(CELL type, CELL capacity, CELL fill)
 		memset((void*)AREF(array,0),'\0',capacity * CELLS);
 	else
 	{
+		/* No need for write barrier here. Either the object is in
+		the nursery, or it was allocated directly in tenured space
+		and the write barrier is already hit for us in that case. */
 		for(i = 0; i < capacity; i++)
-			set_array_nth(array,i,fill);
+			put(AREF(array,i),fill);
 	}
 	return array;
 }
@@ -181,7 +185,7 @@ F_ARRAY *reallot_array(F_ARRAY* array, CELL capacity, CELL fill)
 	memcpy(new_array + 1,array + 1,to_copy * CELLS);
 
 	for(i = to_copy; i < capacity; i++)
-		set_array_nth(new_array,i,fill);
+		put(AREF(new_array,i),fill);
 
 	return new_array;
 }
@@ -222,6 +226,8 @@ F_ARRAY *growable_append(F_ARRAY *result, F_ARRAY *elts, CELL *result_count)
 
 	UNREGISTER_UNTAGGED(elts);
 
+	write_barrier((CELL)result);
+
 	memcpy((void*)AREF(result,*result_count),(void*)AREF(elts,0),elts_size * CELLS);
 
 	*result_count += elts_size;
@@ -467,6 +473,8 @@ void set_string_nth(F_STRING* string, CELL index, CELL value)
 				untag_fixnum_fast(string->length)
 				* sizeof(u16));
 			UNREGISTER_UNTAGGED(string);
+
+			write_barrier((CELL)string);
 			string->aux = tag_object(aux);
 		}
 	}
@@ -549,10 +557,11 @@ F_STRING* reallot_string(F_STRING* string, CELL capacity, CELL fill)
 		REGISTER_UNTAGGED(string);
 		REGISTER_UNTAGGED(new_string);
 		F_BYTE_ARRAY *new_aux = allot_byte_array(capacity * sizeof(u16));
-		new_string->aux = tag_object(new_aux);
 		UNREGISTER_UNTAGGED(new_string);
 		UNREGISTER_UNTAGGED(string);
 
+		new_string->aux = tag_object(new_aux);
+
 		F_BYTE_ARRAY *aux = untag_object(string->aux);
 		memcpy(new_aux + 1,aux + 1,to_copy * sizeof(u16));
 	}