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！
default:
                throw JSONRPCError(RPC_MISC_ERROR, errors[0]);
                break;
        }
    }
    UniValue result(UniValue::VOBJ);
    
    
    if (!pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
        if (!feebumper::SignTransaction(*pwallet, mtx)) {
            throw JSONRPCError(RPC_WALLET_ERROR, "Can't sign transaction.");
        }
        uint256 txid;
        if (feebumper::CommitTransaction(*pwallet, hash, std::move(mtx), errors, txid) != feebumper::Result::OK) {
            throw JSONRPCError(RPC_WALLET_ERROR, errors[0]);
        }
        result.pushKV("txid", txid.GetHex());
    } else {
        PartiallySignedTransaction psbtx(mtx);
        bool complete = false;
        const TransactionError err = pwallet->FillPSBT(psbtx, complete, SIGHASH_ALL, false , true );
        CHECK_NONFATAL(err == TransactionError::OK);
        CHECK_NONFATAL(!complete);
        CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
        ssTx << psbtx;
        result.pushKV("psbt", EncodeBase64(ssTx.str()));
    }
    result.pushKV("origfee", ValueFromAmount(old_fee));
    result.pushKV("fee", ValueFromAmount(new_fee));
    UniValue result_errors(UniValue::VARR);