Zombie process is a process that shows up in syslocks but not in sysprocesses table. we need to either reboot the sybase server or use dbcc lock_release option to clear the process(to be done very carefully), else it can cause database corruption.

select spid from syslocks where spid not in (select spid from sysprocesses)

Example:

Here, spid 71 is Zombie process.

1>select * from sysprocesses where spid =71
2>go
(0 rows affected)

1> sp_who '71'
2> go

(0 rows affected)

1> sp_lock 71
2> go

fid spid loid locktype table_id page row dbname class context.

  0     71         122 Ex_intent                      345677888           0      0 abc           Non Cursor Lock
  0     71         122 Ex_intent                      564567889           0      0 abc     Non Cursor Lock