diff --git a/libguile/vm.c b/libguile/vm.c
index 7720afaca..83a2b21af 100644
--- a/libguile/vm.c
+++ b/libguile/vm.c
@@ -605,6 +605,7 @@ return_unused_stack_to_os (struct scm_vm *vp)
       do
         ret = madvise ((void *) lo, hi - lo, MADV_DONTNEED);
       while (ret && errno == -EAGAIN);
+      while (ret && errno == EAGAIN);
 
       if (ret)
         perror ("madvise failed");