diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
index b1a2032ea8..f968869bf5 100644
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -205,7 +205,6 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     entry.nFee = 11;
     entry.nHeight = 11;
 
-    LOCK(cs_main);
     fCheckpointsEnabled = false;
 
     // Simple block creation, nothing special yet:
@@ -218,27 +217,32 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     for (unsigned int i = 0; i < sizeof(blockinfo)/sizeof(*blockinfo); ++i)
     {
         CBlock *pblock = &pblocktemplate->block; // pointer for convenience
-        pblock->nVersion = 1;
-        pblock->nTime = chainActive.Tip()->GetMedianTimePast()+1;
-        CMutableTransaction txCoinbase(*pblock->vtx[0]);
-        txCoinbase.nVersion = 1;
-        txCoinbase.vin[0].scriptSig = CScript();
-        txCoinbase.vin[0].scriptSig.push_back(blockinfo[i].extranonce);
-        txCoinbase.vin[0].scriptSig.push_back(chainActive.Height());
-        txCoinbase.vout.resize(1); // Ignore the (optional) segwit commitment added by CreateNewBlock (as the hardcoded nonces don't account for this)
-        txCoinbase.vout[0].scriptPubKey = CScript();
-        pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
-        if (txFirst.size() == 0)
-            baseheight = chainActive.Height();
-        if (txFirst.size() < 4)
-            txFirst.push_back(pblock->vtx[0]);
-        pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
-        pblock->nNonce = blockinfo[i].nonce;
+        {
+            LOCK(cs_main);
+            pblock->nVersion = 1;
+            pblock->nTime = chainActive.Tip()->GetMedianTimePast()+1;
+            CMutableTransaction txCoinbase(*pblock->vtx[0]);
+            txCoinbase.nVersion = 1;
+            txCoinbase.vin[0].scriptSig = CScript();
+            txCoinbase.vin[0].scriptSig.push_back(blockinfo[i].extranonce);
+            txCoinbase.vin[0].scriptSig.push_back(chainActive.Height());
+            txCoinbase.vout.resize(1); // Ignore the (optional) segwit commitment added by CreateNewBlock (as the hardcoded nonces don't account for this)
+            txCoinbase.vout[0].scriptPubKey = CScript();
+            pblock->vtx[0] = MakeTransactionRef(std::move(txCoinbase));
+            if (txFirst.size() == 0)
+                baseheight = chainActive.Height();
+            if (txFirst.size() < 4)
+                txFirst.push_back(pblock->vtx[0]);
+            pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
+            pblock->nNonce = blockinfo[i].nonce;
+        }
         std::shared_ptr<const CBlock> shared_pblock = std::make_shared<const CBlock>(*pblock);
         BOOST_CHECK(ProcessNewBlock(chainparams, shared_pblock, true, nullptr));
         pblock->hashPrevBlock = pblock->GetHash();
     }
 
+    LOCK(cs_main);
+
     // Just to make sure we can still make simple blocks
     BOOST_CHECK(pblocktemplate = AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey));
 
diff --git a/src/test/txvalidationcache_tests.cpp b/src/test/txvalidationcache_tests.cpp
index fe8cb6126e..10acabe0be 100644
--- a/src/test/txvalidationcache_tests.cpp
+++ b/src/test/txvalidationcache_tests.cpp
@@ -66,7 +66,6 @@ BOOST_FIXTURE_TEST_CASE(tx_mempool_block_doublespend, TestChain100Setup)
 
     // Test 1: block with both of those transactions should be rejected.
     block = CreateAndProcessBlock(spends, scriptPubKey);
-    LOCK(cs_main);
     BOOST_CHECK(chainActive.Tip()->GetBlockHash() != block.GetHash());
 
     // Test 2: ... and should be rejected if spend1 is in the memory pool
@@ -190,12 +189,12 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup)
         spend_tx.vin[0].scriptSig << vchSig;
     }
 
-    LOCK(cs_main);
-
     // Test that invalidity under a set of flags doesn't preclude validity
     // under other (eg consensus) flags.
     // spend_tx is invalid according to DERSIG
     {
+        LOCK(cs_main);
+
         CValidationState state;
         PrecomputedTransactionData ptd_spend_tx(spend_tx);
 
@@ -213,16 +212,18 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup)
         // test later that block validation works fine in the absence of cached
         // successes.
         ValidateCheckInputsForAllFlags(spend_tx, SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_LOW_S | SCRIPT_VERIFY_STRICTENC, false);
-
-        // And if we produce a block with this tx, it should be valid (DERSIG not
-        // enabled yet), even though there's no cache entry.
-        CBlock block;
-
-        block = CreateAndProcessBlock({spend_tx}, p2pk_scriptPubKey);
-        BOOST_CHECK(chainActive.Tip()->GetBlockHash() == block.GetHash());
-        BOOST_CHECK(pcoinsTip->GetBestBlock() == block.GetHash());
     }
 
+    // And if we produce a block with this tx, it should be valid (DERSIG not
+    // enabled yet), even though there's no cache entry.
+    CBlock block;
+
+    block = CreateAndProcessBlock({spend_tx}, p2pk_scriptPubKey);
+    BOOST_CHECK(chainActive.Tip()->GetBlockHash() == block.GetHash());
+    BOOST_CHECK(pcoinsTip->GetBestBlock() == block.GetHash());
+
+    LOCK(cs_main);
+
     // Test P2SH: construct a transaction that is valid without P2SH, and
     // then test validity with P2SH.
     {
diff --git a/src/validation.cpp b/src/validation.cpp
index 75c40b22fc..71a51c499c 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2559,6 +2559,7 @@ bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams&
     // far from a guarantee. Things in the P2P/RPC will often end up calling
     // us in the middle of ProcessNewBlock - do not assume pblock is set
     // sanely for performance or correctness!
+    AssertLockNotHeld(cs_main);
 
     CBlockIndex *pindexMostWork = nullptr;
     CBlockIndex *pindexNewTip = nullptr;
@@ -3383,6 +3384,8 @@ bool CChainState::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CVali
 
 bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock> pblock, bool fForceProcessing, bool *fNewBlock)
 {
+    AssertLockNotHeld(cs_main);
+
     {
         CBlockIndex *pindex = nullptr;
         if (fNewBlock) *fNewBlock = false;
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index 80e31a1ce0..8e9362c649 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -370,8 +370,6 @@ static void AddKey(CWallet& wallet, const CKey& key)
 
 BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
 {
-    LOCK(cs_main);
-
     // Cap last block file size, and mine new block in a new block file.
     CBlockIndex* const nullBlock = nullptr;
     CBlockIndex* oldTip = chainActive.Tip();
@@ -379,6 +377,8 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
     CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
     CBlockIndex* newTip = chainActive.Tip();
 
+    LOCK(cs_main);
+
     // Verify ScanForWalletTransactions picks up transactions in both the old
     // and new block files.
     {
@@ -447,8 +447,6 @@ BOOST_FIXTURE_TEST_CASE(rescan, TestChain100Setup)
 // than or equal to key birthday.
 BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
 {
-    LOCK(cs_main);
-
     // Create two blocks with same timestamp to verify that importwallet rescan
     // will pick up both blocks, not just the first.
     const int64_t BLOCK_TIME = chainActive.Tip()->GetBlockTimeMax() + 5;
@@ -462,6 +460,8 @@ BOOST_FIXTURE_TEST_CASE(importwallet_rescan, TestChain100Setup)
     SetMockTime(KEY_TIME);
     coinbaseTxns.emplace_back(*CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey())).vtx[0]);
 
+    LOCK(cs_main);
+
     // Import key into wallet and call dumpwallet to create backup file.
     {
         CWallet wallet;
@@ -627,10 +627,15 @@ public:
         BOOST_CHECK(wallet->CreateTransaction({recipient}, wtx, reservekey, fee, changePos, error, dummy));
         CValidationState state;
         BOOST_CHECK(wallet->CommitTransaction(wtx, reservekey, nullptr, state));
+        CMutableTransaction blocktx;
+        {
+            LOCK(wallet->cs_wallet);
+            blocktx = CMutableTransaction(*wallet->mapWallet.at(wtx.GetHash()).tx);
+        }
+        CreateAndProcessBlock({CMutableTransaction(blocktx)}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
         LOCK(wallet->cs_wallet);
         auto it = wallet->mapWallet.find(wtx.GetHash());
         BOOST_CHECK(it != wallet->mapWallet.end());
-        CreateAndProcessBlock({CMutableTransaction(*it->second.tx)}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
         it->second.SetMerkleBranch(chainActive.Tip(), 1);
         return it->second;
     }
@@ -641,7 +646,6 @@ public:
 BOOST_FIXTURE_TEST_CASE(ListCoins, ListCoinsTestingSetup)
 {
     std::string coinbaseAddress = coinbaseKey.GetPubKey().GetID().ToString();
-    LOCK2(cs_main, wallet->cs_wallet);
 
     // Confirm ListCoins initially returns 1 coin grouped under coinbaseKey
     // address.
@@ -669,6 +673,7 @@ BOOST_FIXTURE_TEST_CASE(ListCoins, ListCoinsTestingSetup)
     BOOST_CHECK_EQUAL(available.size(), 2);
     for (const auto& group : list) {
         for (const auto& coin : group.second) {
+            LOCK(wallet->cs_wallet);
             wallet->LockCoin(COutPoint(coin.tx->GetHash(), coin.i));
         }
     }