ORA-4031 and ORA-600 [723] in ASM alert log on rebalance operation

Had an interesting support call the other day. Customer reported ORA-4031 and ORA-600 [723] in ASM alert log on rebalance operation. Not a big deal, right?

Closer look at ORA-600 [723] trace file showed memory leak with "KFNS Locked AU " chunks. ASM alert log also had ORA-600 [kfnsMasterWait01] and ORA-600 [kfgscDelete00] errors. ASM version was 11.1.0.7.1 i.e. 11.1 with PSU 1.

Search for known issues lead me to couple of very bad bugs (9217933 and 9250812), already alerted on Metalink/MOS:

Note:985150.1 - ORA-600 [KFNSMASTERWAIT01] occurs after applying PSU 11.1.0.7.1.

Note:985183.1 - New patch required after installing PSU 11.1.0.7.1 to ASM environments.

Note:9209238.8 - Bug 9209238 - 11.1.0.7.2 Patch Set Update (PSU 2).

In short, if you are on 11.1.0.7.1. you better apply 11.1.0.7.2 (11.1 PSU2).