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.
{
    
    CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
    if (filein.IsNull())
        return error("%s: OpenUndoFile failed", __func__);
    
    uint256 hashChecksum;
    CHashVerifier<CAutoFile> verifier(&filein); 
    try {
        verifier << hashBlock;
        verifier >> blockundo;
        filein >> hashChecksum;
    }
    catch (const std::exception& e) {
        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
    }
    
    if (hashChecksum != verifier.GetHash())
        return error("%s: Checksum mismatch", __func__);
    return true;
}
bool AbortNode(const std::string& strMessage, const std::string& userMessage="")