X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FSparks.c;h=cb3d8d98eb26078b251da845168daeffc8af6ebe;hb=dcd38ff7690eb9bdfefc3e7b5c29b7269149df87;hp=e7273f3ed0167ff1bf7d16daaef2328759f35097;hpb=2b16fa4791b08b02df8461f3b79d0e44d72d0960;p=ghc-hetmet.git

diff --git a/rts/Sparks.c b/rts/Sparks.c
index e7273f3..cb3d8d9 100644
--- a/rts/Sparks.c
+++ b/rts/Sparks.c
@@ -389,6 +389,12 @@ pruneSparkQueue (evac_fn evac, void *user, Capability *cap)
     
     pool = cap->sparks;
     
+    // it is possible that top > bottom, indicating an empty pool.  We
+    // fix that here; this is only necessary because the loop below
+    // assumes it.
+    if (pool->top > pool->bottom)
+        pool->top = pool->bottom;
+
     // Take this opportunity to reset top/bottom modulo the size of
     // the array, to avoid overflow.  This is only possible because no
     // stealing is happening during GC.