diff --git a/src/validation.cpp b/src/validation.cpp
index 203bd576765..91ef961964b 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1485,6 +1485,7 @@ int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out)
  *  When FAILED is returned, view is left in an indeterminate state. */
 DisconnectResult CChainState::DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view)
 {
+    AssertLockHeld(::cs_main);
     bool fClean = true;
 
     CBlockUndo blockUndo;
diff --git a/src/validation.h b/src/validation.h
index 9385dfdab47..2609538ecec 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -718,7 +718,8 @@ public:
     bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, CBlockIndex** ppindex, bool fRequested, const FlatFilePos* dbp, bool* fNewBlock) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
     // Block (dis)connection on a given view:
-    DisconnectResult DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view);
+    DisconnectResult DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view)
+        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
     bool ConnectBlock(const CBlock& block, BlockValidationState& state, CBlockIndex* pindex,
                       CCoinsViewCache& view, bool fJustCheck = false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);