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！
ret.pushKVs(detail);
    
    
    
    if ((pwallet->chain().rpcEnableDeprecated("label")) && (pwallet->mapAddressBook.count(dest))) {
        ret.pushKV("label", pwallet->mapAddressBook.at(dest).name);
    }
    ret.pushKV("ischange", pwallet->IsChange(scriptPubKey));
    ScriptPubKeyMan* spk_man = pwallet->GetScriptPubKeyMan(scriptPubKey);
    if (spk_man) {
        if (const CKeyMetadata* meta = spk_man->GetMetadata(dest)) {
            ret.pushKV("timestamp", meta->nCreateTime);
            if (meta->has_key_origin) {
                ret.pushKV("hdkeypath", WriteHDKeypath(meta->key_origin.path));
                ret.pushKV("hdseedid", meta->hd_seed_id.GetHex());
                ret.pushKV("hdmasterfingerprint", HexStr(meta->key_origin.fingerprint, meta->key_origin.fingerprint + 4));
            }
        }
    }
    
    
    
    
    
    UniValue labels(UniValue::VARR);
    std::map<CTxDestination, CAddressBookData>::const_iterator mi = pwallet->mapAddressBook.find(dest);
    if (mi != pwallet->mapAddressBook.end()) {
        
        
        if (pwallet->chain().rpcEnableDeprecated("labelspurpose")) {