[EN] ORA-27303: additional information: startup egid = 1000 (oinstall), current egid = 1300 (dba)

On one of our test database server we have 3 standalone databases. On 2 of them we saw following alertlog warnings and they were both down.

Thu Nov 29 11:04:27 2018
Errors in file /u02/app/oracle/diag/rdbms/dbx/DBX/trace/DBX_j000_38928500.trc:
ORA-27140: attach to post/wait facility failed
ORA-27300: OS system dependent operation:invalid_egid failed with status: 1
ORA-27301: OS failure message: Not owner
ORA-27302: failure occurred at: skgpwinit6
ORA-27303: additional information: startup egid = 1000 (oinstall), current egid = 1300 (dba)
Process J000 died, see its trace file
kkjcre1p: unable to spawn jobq slave process

We find out that UNIX group ownership of "oracle" file in DB_HOME/bin directory somehow changed.

Abnormal permissions:
-rwsr-s--x    1 oracle   dba       310184184 Sep 27 11:59 oracle

Normal permissions:
-rwsr-s--x    1 oracle   oinstall  310077325 Nov 11 2017  oracle

GRID_HOME/bin permissions was fine. But you should check them too. We gracefully shut down or aborted all databases and changed the ownership:

cd DB_HOME/bin
chown oracle:oinstall oracle
chmod 6751 oracle

Then started all databases and everything was fine.