1 files changed, 22 insertions, 17 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 14d60bb26..371460a6f 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -547,8 +547,10 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
     const CTransaction& tx = *ptx;
     const uint256 hash = tx.GetHash();
     AssertLockHeld(cs_main);
-    if (pfMissingInputs)
+    LOCK(pool.cs); // mempool "read lock" (held through GetMainSignals().TransactionAddedToMempool())
+    if (pfMissingInputs) {
         *pfMissingInputs = false;
+    }
 
     if (!CheckTransaction(tx, state))
         return false; // state filled in by CheckTransaction
@@ -581,8 +583,6 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
 
     // Check for conflicts with in-memory transactions
     std::set<uint256> setConflicts;
-    {
-    LOCK(pool.cs); // protect pool.mapNextTx
     for (const CTxIn &txin : tx.vin)
     {
         auto itConflicting = pool.mapNextTx.find(txin.prevout);
@@ -623,15 +623,12 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
             }
         }
     }
-    }
 
     {
         CCoinsView dummy;
         CCoinsViewCache view(&dummy);
 
         LockPoints lp;
-        {
-        LOCK(pool.cs);
         CCoinsViewMemPool viewMemPool(pcoinsTip.get(), pool);
         view.SetBackend(viewMemPool);
 
@@ -670,8 +667,6 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
         if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp))
             return state.DoS(0, false, REJECT_NONSTANDARD, "non-BIP68-final");
 
-        } // end LOCK(pool.cs)
-
         CAmount nFees = 0;
         if (!Consensus::CheckTxInputs(tx, state, view, GetSpendHeight(view), nFees)) {
             return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), FormatStateMessage(state));
@@ -768,7 +763,6 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
         // If we don't hold the lock allConflicting might be incomplete; the
         // subsequent RemoveStaged() and addUnchecked() calls don't guarantee
         // mempool consistency for us.
-        LOCK(pool.cs);
         const bool fReplacementTransaction = setConflicts.size();
         if (fReplacementTransaction)
         {
@@ -1121,7 +1115,13 @@ bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus:
 
 bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
 {
-    if (!ReadBlockFromDisk(block, pindex->GetBlockPos(), consensusParams))
+    CDiskBlockPos blockPos;
+    {
+        LOCK(cs_main);
+        blockPos = pindex->GetBlockPos();
+    }
+
+    if (!ReadBlockFromDisk(block, blockPos, consensusParams))
         return false;
     if (block.GetHash() != pindex->GetBlockHash())
         return error("ReadBlockFromDisk(CBlock&, CBlockIndex*): GetHash() doesn't match index for %s at %s",
@@ -1182,7 +1182,8 @@ static void AlertNotify(const std::string& strMessage)
     safeStatus = singleQuote+safeStatus+singleQuote;
     boost::replace_all(strCmd, "%s", safeStatus);
 
-    boost::thread t(runCommand, strCmd); // thread runs free
+    std::thread t(runCommand, strCmd);
+    t.detach(); // thread runs free
 }
 
 static void CheckForkWarningConditions()
@@ -1683,9 +1684,9 @@ int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Para
     int32_t nVersion = VERSIONBITS_TOP_BITS;
 
     for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
-        ThresholdState state = VersionBitsState(pindexPrev, params, (Consensus::DeploymentPos)i, versionbitscache);
+        ThresholdState state = VersionBitsState(pindexPrev, params, static_cast<Consensus::DeploymentPos>(i), versionbitscache);
         if (state == THRESHOLD_LOCKED_IN || state == THRESHOLD_STARTED) {
-            nVersion |= VersionBitsMask(params, (Consensus::DeploymentPos)i);
+            nVersion |= VersionBitsMask(params, static_cast<Consensus::DeploymentPos>(i));
         }
     }
 
@@ -2571,13 +2572,10 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
         if (GetMainSignals().CallbacksPending() > 10) {
             // Block until the validation queue drains. This should largely
             // never happen in normal operation, however may happen during
-            // reindex, causing memory blowup  if we run too far ahead.
+            // reindex, causing memory blowup if we run too far ahead.
             SyncWithValidationInterfaceQueue();
         }
 
-        if (ShutdownRequested())
-            break;
-
         const CBlockIndex *pindexFork;
         bool fInitialDownload;
         {
@@ -2624,6 +2622,13 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
         }
 
         if (nStopAtHeight && pindexNewTip && pindexNewTip->nHeight >= nStopAtHeight) StartShutdown();
+
+        // We check shutdown only after giving ActivateBestChainStep a chance to run once so that we
+        // never shutdown before connecting the genesis block during LoadChainTip(). Previously this
+        // caused an assert() failure during shutdown in such cases as the UTXO DB flushing checks
+        // that the best block hash is non-null.
+        if (ShutdownRequested())
+            break;
     } while (pindexNewTip != pindexMostWork);
     CheckBlockIndex(chainparams.GetConsensus());