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！
{
    if (pwallet->IsLocked()) {
        throw JSONRPCError(RPC_WALLET_UNLOCK_NEEDED, "Error: Please enter the wallet passphrase with walletpassphrase first.");
    }
}
LegacyScriptPubKeyMan& EnsureLegacyScriptPubKeyMan(CWallet& wallet, bool also_create)
{
    LegacyScriptPubKeyMan* spk_man = wallet.GetLegacyScriptPubKeyMan();
    if (!spk_man && also_create) {
        spk_man = wallet.GetOrCreateLegacyScriptPubKeyMan();
    }
    if (!spk_man) {
        throw JSONRPCError(RPC_WALLET_ERROR, "This type of wallet does not support this command");
    }
    return *spk_man;
}
static void WalletTxToJSON(interfaces::Chain& chain, interfaces::Chain::Lock& locked_chain, const CWalletTx& wtx, UniValue& entry)
{
    int confirms = wtx.GetDepthInMainChain();
    entry.pushKV("confirmations", confirms);
    if (wtx.IsCoinBase())
        entry.pushKV("generated", true);
    if (confirms > 0)
    {
        entry.pushKV("blockhash", wtx.m_confirm.hashBlock.GetHex());
        entry.pushKV("blockheight", wtx.m_confirm.block_height);