rpc: Extend scope of validation mutex in generateblock

MarcoFalke · MarcoFalke · commit 621c634b7fe1 · 2025-01-02T14:16:50.000+01:00
The mutex (required by TestBlockValidity) must be held after creating the block, until TestBlockValidity is called. Otherwise, it is possible that the chain advances in the meantime and leads to a crash in TestBlockValidity: Assertion failed: pindexPrev && pindexPrev == chainstate.m_chain.Tip() (validation.cpp: TestBlockValidity: 4338) The diff can be reviewed with the git options --ignore-all-space --function-context Github-Pull: 31563 Rebased-From: fa62c8b
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
@@ -1,5 +1,5 @@
 // Copyright (c) 2010 Satoshi Nakamoto
-// Copyright (c) 2009-2022 The Bitcoin Core developers
+// Copyright (c) 2009-present The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -370,20 +370,21 @@ static RPCHelpMan generateblock()
 
     ChainstateManager& chainman = EnsureChainman(node);
     {
-        std::unique_ptr<CBlockTemplate> blocktemplate{miner.createNewBlock(coinbase_script, {.use_mempool = false})};
-        if (!blocktemplate) {
-            throw JSONRPCError(RPC_INTERNAL_ERROR, "Couldn't create new block");
+        LOCK(chainman.GetMutex());
+        {
+            std::unique_ptr<CBlockTemplate> blocktemplate{miner.createNewBlock(coinbase_script, {.use_mempool = false})};
+            if (!blocktemplate) {
+                throw JSONRPCError(RPC_INTERNAL_ERROR, "Couldn't create new block");
+            }
+            block = blocktemplate->block;
         }
-        block = blocktemplate->block;
-    }
 
-    CHECK_NONFATAL(block.vtx.size() == 1);
+        CHECK_NONFATAL(block.vtx.size() == 1);
 
-    // Add transactions
-    block.vtx.insert(block.vtx.end(), txs.begin(), txs.end());
-    RegenerateCommitments(block, chainman);
+        // Add transactions
+        block.vtx.insert(block.vtx.end(), txs.begin(), txs.end());
+        RegenerateCommitments(block, chainman);
 
-    {
         BlockValidationState state;
         if (!miner.testBlockValidity(block, /*check_merkle_root=*/false, state)) {
             throw JSONRPCError(RPC_VERIFY_ERROR, strprintf("testBlockValidity failed: %s", state.ToString()));
