1 files changed, 14 insertions, 4 deletions
diff --git a/rts/Weak.c b/rts/Weak.c
index ec998c214f..fe4516794a 100644
--- a/rts/Weak.c
+++ b/rts/Weak.c
@@ -93,9 +93,19 @@ scheduleFinalizers(Capability *cap, StgWeak *list)
     StgWord size;
     uint32_t n, i;
 
-    ASSERT(n_finalizers == 0);
-
-    finalizer_list = list;
+    // This assertion does not hold with non-moving collection because
+    // non-moving collector does not wait for the list to be consumed (by
+    // doIdleGcWork()) before appending the list with more finalizers.
+    ASSERT(RtsFlags.GcFlags.useNonmoving || n_finalizers == 0);
+
+    // Append finalizer_list with the new list. TODO: Perhaps cache tail of the
+    // list for faster append. NOTE: We can't append `list` here! Otherwise we
+    // end up traversing already visited weaks in the loops below.
+    StgWeak **tl = &finalizer_list;
+    while (*tl) {
+        tl = &(*tl)->link;
+    }
+    *tl = list;
 
     // Traverse the list and
     //  * count the number of Haskell finalizers
@@ -130,7 +140,7 @@ scheduleFinalizers(Capability *cap, StgWeak *list)
         SET_HDR(w, &stg_DEAD_WEAK_info, w->header.prof.ccs);
     }
 
-    n_finalizers = i;
+    n_finalizers += i;
 
     // No Haskell finalizers to run?
     if (n == 0) return;