IV80830: UNIX OS AGENT MAY CORRUPT MEMORY WHILE COLLECTING METRICS FOR THE DISK GROUP.

IBM Tivoli Monitoring: Unix(R) OS Agent 6.3.0.5-TIV-ITM_UNIX-IF0004
IBM Tivoli Monitoring 6.3.0 Fix Pack 7 (6.3.0-TIV-ITM-FP0007)

APAR status

• Closed as program error.

Error description

• Random memory corruptions may occur in the UNIX OS Agent while
  collecting metrics for the Disk group
  Affected Platforms / Versions:
   This issue affects all the UNIXX OS agent versions since 6.23
  FP1 and
   it does not depend on the UNIX platform.
  
  Diagnostics:
   RAS1 logs at ERROR level show a sequence like this before
  ending:
  
  mount_stat.cpp,446,"get_mount_info")
    WARNING: The statvfs64 timeout expired!
  mount_stat.cpp,447,"get_mount_info")
    WARNING: The mounted file system "/example/file/system is
  probably unreachable
  .
  With more detailed RAS1 logging enabled, RAS logs will end with
  the thread
  for "exec_statvfs64":
  mount_stat.cpp,189,"exec_statvfs64") statvfs64 executed
  successfully for "/example/file/system"
  mount_stat.cpp,294,"exec_statvfs64") Exit: 0x0
  .
  The traceback of the coring thread is variable as this issue is
  the result of
  memory corruption when the call to statvfs64() returns and the
  "exec_stavtfs64"
  thread exits, where the calling thread has previously timed out.
  .
  Initial Impact:
   High - monitoring agent crashes.
  .
  Additional Keywords:
   UNIXDISK
   core
   dump
   sigsegv
   mount_stat
   kuxagent
  
  Local Fix:
   Increase KBB_NFS_TIMEOUT to prevent timeout of statvfs64
  

Local fix

• Increase KBB_NFS_TIMEOUT setting to larger value than the
  statfvs64 call takes to return. Set in lz.ini and value is
  specified in seconds.
  

Problem summary

• Problem Description: The Monitoring Agent for UNIX OS may
   corrupt memory while monitoring disks.
  Problem/Problem Summary: A condition has been identified where
   the buffer containing data for a filesystem can be overridden
   by those for another filesystem. This memory corruption is
   caused by a timing condition between two agent internal threads
   and it may occur when one or more filesystems do not respond
   within the 2 seconds default timeout for the statvfs64 system
   call.
  

Problem conclusion

• Fix/Problem Conclusion: Memory corruption avoided.
  
  The fix for this APAR will be contained in the following
  maintenance packages:
  
  | FixPack    | 6.3.0-TIV-ITM-FP0007
  | InterimFix | 6.3.0.5-TIV-ITM_UNIX-IF0004
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IV80542

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  ITM AGENT UNIX

• Fixed component ID

  5724C040U

Applicable component levels