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！
{
    return{{RPCResult::Type::NUM, "confirmations", "The number of confirmations for the transaction. Negative confirmations means the\n"
               "transaction conflicted that many blocks ago."},
           {RPCResult::Type::BOOL, "generated", "Only present if transaction only input is a coinbase one."},
           {RPCResult::Type::BOOL, "trusted", "Only present if we consider transaction to be trusted and so safe to spend from."},
           {RPCResult::Type::STR_HEX, "blockhash", "The block hash containing the transaction."},
           {RPCResult::Type::NUM, "blockheight", "The block height containing the transaction."},
           {RPCResult::Type::NUM, "blockindex", "The index of the transaction in the block that includes it."},
           {RPCResult::Type::NUM_TIME, "blocktime", "The block time expressed in " + UNIX_EPOCH_TIME + "."},
           {RPCResult::Type::STR_HEX, "txid", "The transaction id."},
           {RPCResult::Type::ARR, "walletconflicts", "Conflicting transaction ids.",
           {
               {RPCResult::Type::STR_HEX, "txid", "The transaction id."},
           }},
           {RPCResult::Type::NUM_TIME, "time", "The transaction time expressed in " + UNIX_EPOCH_TIME + "."},
           {RPCResult::Type::NUM_TIME, "timereceived", "The time received expressed in " + UNIX_EPOCH_TIME + "."},
           {RPCResult::Type::STR, "comment", "If a comment is associated with the transaction, only present if not empty."},
           {RPCResult::Type::STR, "bip125-replaceable", "(\"yes|no|unknown\") Whether this transaction could be replaced due to BIP125 (replace-by-fee);\n"
               "may be unknown for unconfirmed transactions not in the mempool"}};
}
UniValue listtransactions(const JSONRPCRequest& request)