ORA-600 [KGHLKREM1] On Linux Using Parameter drop_cache On hugepages Configuration
(Doc ID 1070812.1)
Last updated on MARCH 18, 2019
Applies to:Oracle Database - Enterprise Edition - Version 10.2.0.1 and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
***Checked for relevance on 29-Jul-2013***
You are running an Oracle Database, single-instance or RAC. You have the SGA backed by hugepages.
You are getting the error
with stack trace similar to: kghnerror kghadd_reserved_ext kghgex
-- or also
ORA-07445: exception encountered: core dump
[kglhdal()+1105][SIGSEGV] [Address not mapped to object] [0x000000008]  
ORA-07445: exception encountered: core dump [kghfnd()+2328] [SIGSEGV]
[Address not mapped to object] [0xFFFFFFFFFFFFFFF0]  
Also the SGA heap Dump of memory around the offending addr (in this particular example: 0x6bc00020) shows it is zeroed out:
*** 2010-02-08 15:57:38.274
***** Internal heap ERROR KGHLKREM1 addr=0x6c400020 ds=0x60000058 *****
***** Dump of memory around addr 0x6c400020:
06C3FF020 00000000 00000000 00000000 00000000 [................]
Repeat 511 times
1. On your system you are running with vm.drop_caches=1 (or 3), drop_cache have been setto a value greater than zero , or you are executing
Writing to this file causes the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free.
To free pagecache:
* echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
* echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:
* echo 3 > /proc/sys/vm/drop_caches
As this is a non-destructive operation, and dirty objects are not freeable, the user should run "sync" first in order to make sure all cached objects are freed.
2. You have setup the Hugepages
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