diff --git a/src/mzscheme/gc2/compact.c b/src/mzscheme/gc2/compact.c
index 38e34240c8..20fd4084fa 100644
--- a/src/mzscheme/gc2/compact.c
+++ b/src/mzscheme/gc2/compact.c
@@ -2976,7 +2976,7 @@ static void gcollect(int full)
   getrusage(RUSAGE_SELF, &pre);
 #endif
 
-  sort_and_merge_roots();
+  sort_and_merge_roots(&GC->roots);
 
   during_gc = 1;
 
diff --git a/src/mzscheme/gc2/newgc.c b/src/mzscheme/gc2/newgc.c
index b46af4bc74..1c71c55592 100644
--- a/src/mzscheme/gc2/newgc.c
+++ b/src/mzscheme/gc2/newgc.c
@@ -937,7 +937,7 @@ static inline void *get_stack_base() {
   unsigned long j;                                                        \
   Roots *roots = &GC->roots;                                              \
   if(roots->roots) {                                                      \
-    sort_and_merge_roots();                                               \
+    sort_and_merge_roots(roots);                                          \
     for(j = 0; j < roots->count; j += 2) {                                \
       void **start = (void**)roots->roots[j];                             \
       void **end = (void**)roots->roots[j+1];                             \
diff --git a/src/mzscheme/gc2/roots.c b/src/mzscheme/gc2/roots.c
index 5e377f4269..45816430c2 100644
--- a/src/mzscheme/gc2/roots.c
+++ b/src/mzscheme/gc2/roots.c
@@ -33,9 +33,8 @@ static int compare_roots(const void *a, const void *b)
     return 1;
 }
 
-static void sort_and_merge_roots()
+static void sort_and_merge_roots(Roots *roots)
 {
-  Roots *roots = &GC->roots;
   if (roots->nothing_new)
     return;