core: ensure state exists for prefetcher (ethereum#20627)

Author: holiman

core/blockchain.go

@@ -1654,18 +1654,17 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, er
 		// If we have a followup block, run that against the current state to pre-cache
 		// transactions and probabilistically some of the account/storage trie nodes.
 		var followupInterrupt uint32
-
 		if !bc.cacheConfig.TrieCleanNoPrefetch {
 			if followup, err := it.peek(); followup != nil && err == nil {
-				go func(start time.Time) {
-					throwaway, _ := state.New(parent.Root, bc.stateCache)
-					bc.prefetcher.Prefetch(followup, throwaway, bc.vmConfig, &followupInterrupt)
+				throwaway, _ := state.New(parent.Root, bc.stateCache)
+				go func(start time.Time, followup *types.Block, throwaway *state.StateDB, interrupt *uint32) {
+					bc.prefetcher.Prefetch(followup, throwaway, bc.vmConfig, interrupt)
 
 					blockPrefetchExecuteTimer.Update(time.Since(start))
-					if atomic.LoadUint32(&followupInterrupt) == 1 {
+					if atomic.LoadUint32(interrupt) == 1 {
 						blockPrefetchInterruptMeter.Mark(1)
 					}
-				}(time.Now())
+				}(time.Now(), followup, throwaway, &followupInterrupt)
 			}
 		}
 		// Process block using the parent state as reference point