init.cpp:1635 prints mapBlockIndex.size() without cs_main. This is technically a race (though it is rather inconsequential). At some point someone should fix this so tsan stops complaining.
bool* pfMissingInputs, int64_t nAcceptTime, std::list<CTransactionRef>* plTxnReplaced,
                              bool fOverrideMempoolLimit, const CAmount& nAbsurdFee, std::vector<COutPoint>& coins_to_uncache)
{
    const CTransaction& tx = *ptx;
    const uint256 hash = tx.GetHash();
    AssertLockHeld(cs_main);
    if (pfMissingInputs)
        *pfMissingInputs = false;
    if (!CheckTransaction(tx, state))
        return false; 
    
    if (tx.IsCoinBase())
        return state.DoS(100, false, REJECT_INVALID, "coinbase");
    
    bool witnessEnabled = IsWitnessEnabled(chainActive.Tip(), chainparams.GetConsensus());
    if (!gArgs.GetBoolArg("-prematurewitness", false) && tx.HasWitness() && !witnessEnabled) {
        return state.DoS(0, false, REJECT_NONSTANDARD, "no-witness-yet", true);
    }
    
    std::string reason;
    if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
        return state.DoS(0, false, REJECT_NONSTANDARD, reason);
    
    
    
    if (!CheckFinalTx(tx, STANDARD_LOCKTIME_VERIFY_FLAGS))
        return state.DoS(0, false, REJECT_NONSTANDARD, "non-final");