EXP-00008: ORACLE error 600 encountered

Today I was running export of an Oracle database. The export completed but with an ORA-600 error:

EXP-00008: ORACLE error 600 encountered
ORA-00600: internal error code, arguments: [xsoptloc2], [4], [4], [0], [], [], [], []
ORA-06512: in "SYS.DBMS_AW", line 347
ORA-06512: in "SYS.DBMS_AW", line 470
ORA-06512: in "SYS.DBMS_AW_EXP", line 270
ORA-06512: in line 1
EXP-00083: The previous problem occurred when calling SYS.DBMS_AW_EXP.schema_info_exp

I googled a bit and found that the problem is with applying some patchset. Then metalink confirmed the same. Somebody tried applying a patch to upgrade it to but didn’t perform all the steps (missed post installation steps, to be precise). Metalink Note 300849.1 covers the issue and also gives the solution. In nutshell startup the database with startup migrate and run catpatch.sql.