Require CBlockIndex::GetBlockPos() to hold mutex cs_main

src/chain.h

@@ -10,6 +10,7 @@
 #include <consensus/params.h>
 #include <flatfile.h>
 #include <primitives/block.h>
+#include <sync.h>
 #include <tinyformat.h>
 #include <uint256.h>
 
@@ -37,6 +38,8 @@ static constexpr int64_t TIMESTAMP_WINDOW = MAX_FUTURE_BLOCK_TIME;
  */
 static constexpr int64_t MAX_BLOCK_TIME_GAP = 90 * 60;
 
+extern RecursiveMutex cs_main;
+
 class CBlockFileInfo
 {
 public:
@@ -223,8 +226,9 @@ public:
     {
     }
 
-    FlatFilePos GetBlockPos() const
+    FlatFilePos GetBlockPos() const EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
     {
+        AssertLockHeld(::cs_main);
         FlatFilePos ret;
         if (nStatus & BLOCK_HAVE_DATA) {
             ret.nFile = nFile;

src/index/txindex.cpp

@@ -59,7 +59,9 @@ bool TxIndex::WriteBlock(const CBlock& block, const CBlockIndex* pindex)
     // Exclude genesis block transaction because outputs are not spendable.
     if (pindex->nHeight == 0) return true;
 
-    CDiskTxPos pos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size()));
+    CDiskTxPos pos{
+        WITH_LOCK(::cs_main, return pindex->GetBlockPos()),
+        GetSizeOfCompactSize(block.vtx.size())};
     std::vector<std::pair<uint256, CDiskTxPos>> vPos;
     vPos.reserve(block.vtx.size());
     for (const auto& tx : block.vtx) {

src/test/fuzz/chain.cpp

@@ -21,6 +21,8 @@ FUZZ_TARGET(chain)
 
     const uint256 zero{};
     disk_block_index->phashBlock = &zero;
+    {
+        LOCK(::cs_main);
         (void)disk_block_index->GetBlockHash();
         (void)disk_block_index->GetBlockPos();
         (void)disk_block_index->GetBlockTime();
@@ -30,6 +32,7 @@ FUZZ_TARGET(chain)
         (void)disk_block_index->HaveTxsDownloaded();
         (void)disk_block_index->IsValid();
         (void)disk_block_index->ToString();
+    }
 
     const CBlockHeader block_header = disk_block_index->GetBlockHeader();
     (void)CDiskBlockIndex{*disk_block_index};

src/test/util/blockfilter.cpp

@@ -13,6 +13,8 @@ using node::UndoReadFromDisk;
 
 bool ComputeFilter(BlockFilterType filter_type, const CBlockIndex* block_index, BlockFilter& filter)
 {
+    LOCK(::cs_main);
+
     CBlock block;
     if (!ReadBlockFromDisk(block, block_index->GetBlockPos(), Params().GetConsensus())) {
         return false;

src/wallet/test/wallet_tests.cpp

@@ -140,11 +140,13 @@ BOOST_FIXTURE_TEST_CASE(scan_for_wallet_transactions, TestChain100Setup)
     }
 
     // Prune the older block file.
+    int file_number;
     {
         LOCK(cs_main);
-        Assert(m_node.chainman)->m_blockman.PruneOneBlockFile(oldTip->GetBlockPos().nFile);
+        file_number = oldTip->GetBlockPos().nFile;
+        Assert(m_node.chainman)->m_blockman.PruneOneBlockFile(file_number);
     }
-    UnlinkPrunedFiles({oldTip->GetBlockPos().nFile});
+    UnlinkPrunedFiles({file_number});
 
     // Verify ScanForWalletTransactions only picks transactions in the new block
     // file.
@@ -169,9 +171,10 @@ BOOST_FIXTURE_TEST_CASE(scan_for_wallet_transactions, TestChain100Setup)
     // Prune the remaining block file.
     {
         LOCK(cs_main);
-        Assert(m_node.chainman)->m_blockman.PruneOneBlockFile(newTip->GetBlockPos().nFile);
+        file_number = newTip->GetBlockPos().nFile;
+        Assert(m_node.chainman)->m_blockman.PruneOneBlockFile(file_number);
     }
-    UnlinkPrunedFiles({newTip->GetBlockPos().nFile});
+    UnlinkPrunedFiles({file_number});
 
     // Verify ScanForWalletTransactions scans no blocks.
     {
@@ -202,11 +205,13 @@ BOOST_FIXTURE_TEST_CASE(importmulti_rescan, TestChain100Setup)
     CBlockIndex* newTip = m_node.chainman->ActiveChain().Tip();
 
     // Prune the older block file.
+    int file_number;
     {
         LOCK(cs_main);
-        Assert(m_node.chainman)->m_blockman.PruneOneBlockFile(oldTip->GetBlockPos().nFile);
+        file_number = oldTip->GetBlockPos().nFile;
+        Assert(m_node.chainman)->m_blockman.PruneOneBlockFile(file_number);
     }
-    UnlinkPrunedFiles({oldTip->GetBlockPos().nFile});
+    UnlinkPrunedFiles({file_number});
 
     // Verify importmulti RPC returns failure for a key whose creation time is
     // before the missing block, and success for a key whose creation time is