diff --git a/libgomp/env.c b/libgomp/env.c
index 1c4ee894515..dff07617e15 100644
--- a/libgomp/env.c
+++ b/libgomp/env.c
@@ -182,6 +182,8 @@ parse_schedule (void)
     goto invalid;
 
   errno = 0;
+  if (*env == '-')
+    goto invalid;
   value = strtoul (env, &end, 10);
   if (errno || end == env)
     goto invalid;
diff --git a/libgomp/loop.c b/libgomp/loop.c
index be85162bb1e..018b4e9a8bd 100644
--- a/libgomp/loop.c
+++ b/libgomp/loop.c
@@ -41,7 +41,7 @@ gomp_loop_init (struct gomp_work_share *ws, long start, long end, long incr,
 		enum gomp_schedule_type sched, long chunk_size)
 {
   ws->sched = sched;
-  ws->chunk_size = chunk_size;
+  ws->chunk_size = (sched == GFS_STATIC || chunk_size > 1) ? chunk_size : 1;
   /* Canonicalize loops that have zero iterations to ->next == ->end.  */
   ws->end = ((incr > 0 && start > end) || (incr < 0 && start < end))
 	    ? start : end;
diff --git a/libgomp/testsuite/libgomp.c/loop-28.c b/libgomp/testsuite/libgomp.c/loop-28.c
new file mode 100644
index 00000000000..e3f852046f4
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/loop-28.c
@@ -0,0 +1,17 @@
+/* { dg-do run } */
+/* { dg-timeout 10 } */
+
+void __attribute__((noinline))
+foo (int a[], int n, int chunk_size)
+{
+  #pragma omp parallel for schedule (dynamic,chunk_size)
+  for (int i = 0; i < n; i++)
+    a[i] = i;
+}
+
+int main (void)
+{
+  int a[100];
+  foo (a, 100, 0);
+  return 0;
+}