diff --git a/c/srfi/srfi-27.c b/c/srfi/srfi-27.c
index 2e5eab5..77c83e7 100644
--- a/c/srfi/srfi-27.c
+++ b/c/srfi/srfi-27.c
@@ -117,6 +117,12 @@ static double mrg32k3a(state_t *s) { /* (double), in {0..m1-1} */
 s48_value mrg32k3a_pack_state1(s48_value state) {
   s48_value result;
   state_t   s;
+  S48_DECLARE_GC_PROTECT(1);
+
+  S48_GC_PROTECT_1(state); /* s48_extract_integer may GC */
+
+  result = S48_MAKE_VALUE(state_t);
+
 
 #define REF(i) (double)s48_extract_integer(S48_VECTOR_REF(state, (long)(i)))
 
@@ -130,6 +136,8 @@ s48_value mrg32k3a_pack_state1(s48_value state) {
 
 #undef REF
 
+  S48_GC_UNPROTECT();
+
   /* box s into a Scheme object */
   result = S48_MAKE_VALUE(state_t);
   S48_SET_VALUE(result, state_t, s);
@@ -137,9 +145,12 @@ s48_value mrg32k3a_pack_state1(s48_value state) {
 }
 
 s48_value mrg32k3a_unpack_state1(s48_value state) {
-  s48_value result;
+  s48_value result = S48_UNSPECIFIC;
   state_t   s;
 
+  S48_DECLARE_GC_PROTECT(1);
+  S48_GC_PROTECT_1(result);
+
   /* unbox s from the Scheme object */
   s = S48_EXTRACT_VALUE(state, state_t);
 
@@ -161,6 +172,8 @@ s48_value mrg32k3a_unpack_state1(s48_value state) {
 
 #undef SET
 
+  S48_GC_UNPROTECT();
+
   return result;
 }