An Oracle procedure that allow users to kill their own sessions

First, create a view that lets the users check their own sessions:

connect / as sysdba

create or replace view my_sessions as
select username,sid,serial#,osuser,status,program,machine
from v$session
where username=SYS_CONTEXT('userenv','CURRENT_SCHEMA');

Create a public synonym, and grant select to public:

create public synonym my_sessions for my_sessions;
grant select on my_sessions to public;

To get the procedure to compile in the SYSTEM schema, it is required to grant the "alter system" privilege directly to the user - having the same privilege through a role won't do.

grant alter system to system;
grant select on v_$session to system;

Log in as system, and create the procedure:

CREATE OR REPLACE PROCEDURE KILL_SESSION(PN_SID NUMBER,PN_SERIAL NUMBER) AUTHID DEFINER
AS
LV_USER VARCHAR2(30);
EXE_USER VARCHAR2(30);
BEGIN
    SELECT S.USERNAME INTO LV_USER 
    FROM V$SESSION S, USER_USERS U 
    WHERE S.SID    = PN_SID 
    AND S.SERIAL#  = PN_SERIAL
    AND S.USERNAME = S.USERNAME;

    SELECT USERNAME INTO EXE_USER
    FROM V$SESSION 
    WHERE AUDSID=SYS_CONTEXT('userenv','SESSIONID');

 IF EXE_USER = LV_USER THEN
    EXECUTE IMMEDIATE 'alter system kill session '''||PN_SID||','||PN_SERIAL||'''';
    dbms_output.put_line('Session ' || PN_SID || ',' || PN_SERIAL || ' killed.');
ELSE
    RAISE_APPLICATION_ERROR(-20000,'Only your own sessions may be killed.');
END IF;
END;
/  

Create a synonym for the procedure and give everyone execute privileges on it:

CREATE PUBLIC SYNONYM KILL_SESSION FOR KILL_SESSION;
GRANT EXECUTE ON KILL_SESSION TO PUBLIC;

Now the users have a way to check their own sessions, and to terminate them if they chose to do so:

connect scott
select * from my_session;

USERNAME                    SID    SERIAL# OSUSER               STATUS               PROGRAM                                          MACHINE
-------------------- ---------- ---------- -------------------- -------------------- ------------------------------------------------ ----------------------------------------------------------------
SCOTT                        1152       9510 oracle               INACTIVE             sqlplus@myserver.mydomain.com (TNS V1- myserver.mydomain.com
SCOTT                        1726      31531 oracle               ACTIVE               sqlplus@myserver.mydomain.com (TNS V1- myserver.mydomain.com

Kill a session:

scott@mydb>SQL>exec kill_session(1152,9510);

Afterwards, the view will change to show session 1152 to be in status KILLED:

USERNAME                    SID    SERIAL# OSUSER               STATUS               PROGRAM                                          MACHINE
-------------------- ---------- ---------- -------------------- -------------------- ------------------------------------------------ ----------------------------------------------------------------
SCOTT                        1152       9510 oracle               KILLED             sqlplus@myserver.mydomain.com (TNS V1- myserver.mydomain.com
SCOTT                        1726      31531 oracle               ACTIVE               sqlplus@myserver.mydomain.com (TNS V1- myserver.mydomain.com