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！
{"query_options", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED_NAMED_ARG, "JSON with query options",
                        {
                            {"minimumAmount", RPCArg::Type::AMOUNT,  "0", "Minimum value of each UTXO in " + CURRENCY_UNIT + ""},
                            {"maximumAmount", RPCArg::Type::AMOUNT,  "unlimited", "Maximum value of each UTXO in " + CURRENCY_UNIT + ""},
                            {"maximumCount", RPCArg::Type::NUM,  "unlimited", "Maximum number of UTXOs"},
                            {"minimumSumAmount", RPCArg::Type::AMOUNT,  "unlimited", "Minimum sum value of all UTXOs in " + CURRENCY_UNIT + ""},
                        },
                        "query_options"},
                },
                RPCResult{
                    RPCResult::Type::ARR, "", "",
                    {
                        {RPCResult::Type::OBJ, "", "",
                        {
                            {RPCResult::Type::STR_HEX, "txid", "the transaction id"},
                            {RPCResult::Type::NUM, "vout", "the vout value"},
                            {RPCResult::Type::STR, "address", "the bitcoin address"},
                            {RPCResult::Type::STR, "label", "The associated label, or \"\" for the default label"},
                            {RPCResult::Type::STR, "scriptPubKey", "the script key"},
                            {RPCResult::Type::STR_AMOUNT, "amount", "the transaction output amount in " + CURRENCY_UNIT},
                            {RPCResult::Type::NUM, "confirmations", "The number of confirmations"},
                            {RPCResult::Type::STR_HEX, "redeemScript", "The redeemScript if scriptPubKey is P2SH"},
                            {RPCResult::Type::STR, "witnessScript", "witnessScript if the scriptPubKey is P2WSH or P2SH-P2WSH"},
                            {RPCResult::Type::BOOL, "spendable", "Whether we have the private keys to spend this output"},
                            {RPCResult::Type::BOOL, "solvable", "Whether we know how to spend this output, ignoring the lack of keys"},
                            {RPCResult::Type::BOOL, "reused", "(only present if avoid_reuse is set) Whether this output is reused/dirty (sent to an address that was previously spent from)"},
                            {RPCResult::Type::STR, "desc", "(only when solvable) A descriptor for spending this output"},
                            {RPCResult::Type::BOOL, "safe", "Whether this output is considered safe to spend. Unconfirmed transactions\n"
                                                            "from outside keys and unconfirmed replacement transactions are considered unsafe\n"
                                                            "and are not eligible for spending by fundrawtransaction and sendtoaddress."},