Merge bitcoin/bitcoin#22003: txmempool: add thread safety annotations

793b268284 txmempool: add thread safety annotations (Anthony Towns)

Pull request description:

  Add missing thread safety guards to CTxMempool members.

ACKs for top commit:
  MarcoFalke:
    cr ACK 793b268284
  hebasto:
    re-ACK 793b268284, only suggested changes since my [previous](https://github.com/bitcoin/bitcoin/pull/22003#pullrequestreview-664529633) review.

Tree-SHA512: c5eb197c63375c80c325a276f322177e84e0181c94a124720b1a364e964ac223fc6fdfd89bd0e152b76959fb6b97bfbf82dd36ec105ed6e2dc045ede717df4ae

src/test/fuzz/tx_pool.cpp

@@ -21,8 +21,9 @@ std::vector<COutPoint> g_outpoints_coinbase_init_mature;
 std::vector<COutPoint> g_outpoints_coinbase_init_immature;
 
 struct MockedTxPool : public CTxMemPool {
-    void RollingFeeUpdate()
+    void RollingFeeUpdate() EXCLUSIVE_LOCKS_REQUIRED(!cs)
     {
+        LOCK(cs);
         lastRollingFeeUpdate = GetTime();
         blockSinceLastRollingFeeBump = true;
     }

src/txmempool.h

@@ -479,21 +479,21 @@ class CTxMemPool
 protected:
     const int m_check_ratio; //!< Value n means that 1 times in n we check.
     std::atomic<unsigned int> nTransactionsUpdated{0}; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation
-    CBlockPolicyEstimator* minerPolicyEstimator;
+    CBlockPolicyEstimator* const minerPolicyEstimator;
 
     uint64_t totalTxSize GUARDED_BY(cs);      //!< sum of all mempool tx's virtual sizes. Differs from serialized tx size since witness data is discounted. Defined in BIP 141.
     CAmount m_total_fee GUARDED_BY(cs);       //!< sum of all mempool tx's fees (NOT modified fee)
     uint64_t cachedInnerUsage GUARDED_BY(cs); //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
 
-    mutable int64_t lastRollingFeeUpdate;
-    mutable bool blockSinceLastRollingFeeBump;
-    mutable double rollingMinimumFeeRate; //!< minimum fee to get into the pool, decreases exponentially
+    mutable int64_t lastRollingFeeUpdate GUARDED_BY(cs);
+    mutable bool blockSinceLastRollingFeeBump GUARDED_BY(cs);
+    mutable double rollingMinimumFeeRate GUARDED_BY(cs); //!< minimum fee to get into the pool, decreases exponentially
     mutable Epoch m_epoch GUARDED_BY(cs);
 
     // In-memory counter for external mempool tracking purposes.
     // This number is incremented once every time a transaction
     // is added or removed from the mempool for any reason.
-    mutable uint64_t m_sequence_number{1};
+    mutable uint64_t m_sequence_number GUARDED_BY(cs){1};
 
     void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
@@ -587,7 +587,7 @@ private:
 
 public:
     indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs);
-    std::map<uint256, CAmount> mapDeltas;
+    std::map<uint256, CAmount> mapDeltas GUARDED_BY(cs);
 
     /** Create a new CTxMemPool.
      * Sanity checks will be off by default for performance, because otherwise