don't check for stack underflow if we just had an overflow

diff --git a/rts/Schedule.c b/rts/Schedule.c
index 51a8d2a..c840c78 100644 (file)
--- a/rts/Schedule.c
+++ b/rts/Schedule.c
@@ -584,7 +584,9 @@ run_thread:
     
     schedulePostRunThread(cap,t);
 
-    t = threadStackUnderflow(task,t);
+    if (ret != StackOverflow) {
+        t = threadStackUnderflow(task,t);
+    }
 
     ready_to_gc = rtsFalse;