Assistance Required: Timeout or Buffer Overflow Issue in PostgreSQL Client Application

[Sasmit Utkarsh <utkarshsasmit@xxxxxxxxx>]

Dear PostgreSQL Community Team,

I hope this message finds you well. I am reaching out for assistance with an issue encountered in our application, which communicates with PostgreSQL using the libpq client library.

Issue Details:
We have observed a problem where one of the application's threads gets stuck during a database operation. Below is a stack trace of the affected thread:

Application Logs:
Oct 23 10:08:44.806235 cucmtpccu1 shc-server@2.service[966034]: 0966070{ef5f81a7-d35b-4604-953d-a35665e505b7.010000}KIP8-SQL_get_tpf_rw()-SQL read data from File Address before lock fa(-1810606079) fa(94145801) fa2 htonl(22549652)
Oct 23 10:08:44.806235 cucmtpccu1 shc-server@2.service[966034]: 0966070{ef5f81a7-d35b-4604-953d-a35665e505b7.010000}KIP8-SQL_get_tpf_rw() SelectDataCommand = CALL SQL_select_data_procedure($1, $2, NULL, NULL) hold(0) fa(-1810606079)
Oct 23 10:08:44.807814 cucmtpccu1 shc-server@2.service[966034]: *** buffer overflow detected ***: terminated

Stack Trace of Thread 966070:
#0  0x00000000f7ee1129 __kernel_vsyscall (linux-gate.so.1)
#1  0x00000000f6ba23b7 __poll (libc.so.6)
#2  0x00000000f792e5b5 __interceptor_poll (libasan.so.8)
#3  0x00000000f72b30a8 pqSocketCheck (libpq.so.5)
#4  0x00000000f72b3864 pqWaitTimed (libpq.so.5)
#5  0x00000000f72b38d2 pqWait (libpq.so.5)
#6  0x00000000f72aff03 PQgetResult (libpq.so.5)
#7  0x00000000f72b036a PQexecFinish (libpq.so.5)
#8  0x0000000008106dd4 checkLOCK (server)
#9  0x000000000811d871 SQL_get_tpf_rw (server)
...

The stack trace shows that the thread is stuck in a poll operation while waiting for socket activity within the PostgreSQL client library (libpq). We suspect this could be related to a network timeout or issue. However, the application logs indicate a buffer overflow before the crash, which raises questions about whether these are related.

Questions:
-Could the buffer overflow be causing the crash, and if so, how is it related to the socket activity?
-Are there specific configurations or checks we should perform to diagnose this issue further?
-Any suggestions for possible solutions to resolve this problem?

For additional context, I've verified that the specified record does exist in the database, and I am also attaching the implementation details for the checkLOCK function corresponding to the stack trace.

Please let me know if you need any more details 

Your assistance with troubleshooting this would be highly appreciated.

Regards,

Sasmit Utkarsh

+91-7674022625

void checkLOCK(int32_t fa)
{
int         nFields;
int         nTuples;
int         i, j;
PGresult *checkLOCK_res=NULL;
char Command[100];

	LOG_TRACE("%s() fa(%i)(%08X)",__func__,fa,fa);
        
	snprintf(Command,sizeof(Command),"SELECT pid, classid, objid FROM pg_locks WHERE objid=%i",fa);
        //PQclear(checkLOCK_res);
	checkLOCK_res = PQexec(conn,Command);

        if (!checkLOCK_res) {
           LOG_DEBUG("In %s(): PGresult is still NULL so return", __func__);
           return;
        }

        if (PQresultStatus(checkLOCK_res) != PGRES_TUPLES_OK) {
           LOG_DEBUG("checkLOCK failed: %s", PQerrorMessage(conn));
           PQclear(checkLOCK_res);
           return;
        }

        nFields = PQnfields(checkLOCK_res);
        nTuples = PQntuples(checkLOCK_res);

	if(nTuples > 0)
	{
		LOG_DEBUG("%s() fa(%i)(%08X) is currently LOCKED by PID %s as classid=%s objid=%s",__func__,fa,fa,PQgetvalue(checkLOCK_res,0,0),PQgetvalue(checkLOCK_res,0,1),PQgetvalue(checkLOCK_res,0,2));
        	PQclear(checkLOCK_res);
		//printLOCKS();
	}
	else
	{
		LOG_DEBUG("%s() fa(%i)(%08X) is NOT LOCKED",__func__,fa,fa);
        	PQclear(checkLOCK_res);
	}

}