diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index e63b1c6c7..538d955c1 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -5188,6 +5188,8 @@ bool Blockchain::prepare_handle_incoming_blocks(const std::vector<block_complete
         unsigned nblocks = batches;
         if (i < extra)
           ++nblocks;
+        if (nblocks == 0)
+          break;
         tpool.submit(&waiter, boost::bind(&Blockchain::block_longhash_worker, this, thread_height, epee::span<const block>(&blocks[thread_height - height], nblocks), std::ref(maps[i])), true);
         thread_height += nblocks;
       }