When i used the encrypted wallet to test transfer parallelly,i frequently got the trouble: The rpc server is not responding.My test script is like below:
#!/bin/sh
while [ 1 ]
do
./bitcoin-cli listaddressgroupings>null
./bitcoin-cli walletpassphrase "!@#$%^&*" 2
./bitcoin sendtoaddress "mhAW6mzs5DeCbzBUHXBi4U446Fdnr1z8U7" 0.01
done

When i open the dead lock trace macro and check the debug log,i found the last print is as below:
2018-12-17 08:27:58 ThreadRPCServer method=walletpassphrase
2018-12-17 08:27:58 LOCKCONTENTION: cs_main
2018-12-17 08:27:58 Locker: wallet/rpcwallet.cpp:2642
2018-12-17 08:27:58 LOCKCONTENTION: pWallet->cs_wallet
2018-12-17 08:27:58 Locker: wallet/rpcwallet.cpp:2607

The line no 2642 is walletpassphrase and 2607 is LockWallet. I checked the code,i found there is no log printed for this line in function "walletpassphrase":
"LogPrint(BCLog::RPC, "queue run of timer %s in %i seconds (using %s)\n", name, nSeconds, timerInterface->Name());" So i guess the reason may be:
When "walletpassphrase" is running and lock the cs_wallet,the last relock timer triggered and call "LockWallet"."LockWallet" want to lock the cs_wallet but it has been locked by "walletpassphrase",so "LockWallet" is blocked.When "walletpassphrase" run to call "RPCRunLater",the function will erase the timer from the std::map "deadlineTimers",but the timer's timeout call is blocked,so the dead lock take place.
Is my guess right?
How to reslove the issue?
Any help will be appreciative！
{
                        {RPCResult::Type::STR, "name", "The wallet name if loaded successfully."},
                        {RPCResult::Type::STR, "warning", "Warning message if wallet was not loaded cleanly."},
                    }
                },
                RPCExamples{
                    HelpExampleCli("loadwallet", "\"test.dat\"")
            + HelpExampleRpc("loadwallet", "\"test.dat\"")
                },
            }.Check(request);
    WalletLocation location(request.params[0].get_str());
    if (!location.Exists()) {
        throw JSONRPCError(RPC_WALLET_NOT_FOUND, "Wallet " + location.GetName() + " not found.");
    } else if (fs::is_directory(location.GetPath())) {
        
        fs::path wallet_dat_file = location.GetPath() / "wallet.dat";
        if (fs::symlink_status(wallet_dat_file).type() == fs::file_not_found) {
            throw JSONRPCError(RPC_WALLET_NOT_FOUND, "Directory " + location.GetName() + " does not contain a wallet.dat file.");
        }
    }
    std::string error;
    std::vector<std::string> warning;
    std::shared_ptr<CWallet> const wallet = LoadWallet(*g_rpc_chain, location, error, warning);
    if (!wallet) throw JSONRPCError(RPC_WALLET_ERROR, error);
    UniValue obj(UniValue::VOBJ);
    obj.pushKV("name", wallet->GetName());
    obj.pushKV("warning", Join(warning, "\n"));
    return obj;
}
static UniValue setwalletflag(const JSONRPCRequest& request)