Bug 20250147ORA-600 [kjxmgmb_nreq:!bat] can occur in RAC crashing the instance

This note gives a brief overview of bug 20250147.
The content was last updated on: 15-JAN-2020
Clickherefor details of each of the sections below.

Affects:

Product (Component)	Oracle Server (Rdbms)
Range of versionsbelieved to be affected	Versions BELOW 12.2
Versionsconfirmedas being affected	12.1.0.2 (Server Patch Set) 11.2.0.4
Platforms affected	Generic (all / most platforms affected)

Fixed:

The fix for 20250147 is first included in

12.2.0.1 (Base Release) 12.1.0.2.170418 (Apr 2017) Database Patch Set Update (DB PSU) 12.1.0.2.160119 (Jan 2016) Bundle Patch for Engineered Systems / DB In-Memory (DBBP) 11.2.0.4.200114 (Jan 2020) Database Patch Set Update (DB PSU) 11.2.0.4.191015 Exadata Database Bundle Patch (Oct 2019) 12.1.0.2.170418 (Apr 2017) Bundle Patch for Windows Platforms 11.2.0.4.200114 (Jan 2020) Bundle Patch for Windows Platforms

Interim patches may be available for earlier versions - clickhereto check.

Description

This bug is only relevant when using Real Application Clusters (RAC)

LMS2 can raise ORA-600 [kjxmgmb_nreq:!bat], [17], [56],[9] and crash the instance.
 
Rediscovery Notes
 If an LMS raises and assert [kjxmgmb_nreq:!bat], [17], [56],[9]
 when read-mostly object anti-lock expansion times out at an 
 unmounted instance. And if it seen to dissolve the read-mostly 
 object and tries to  send the msg to the tobe master then it could
 be this issue.
 
Workaround
 None