IC65636: MISLEADING MESSAGE "CANNOT LOAD NULL LIBRARY NAME AT ADDRESS" IN INSTANCE MESSAGE LOGFILE ON LINUX

APAR status

• Closed as program error.

Error description

• On any current Linux system one can expect a virtual dynamic
  shared object (vdso) to appear in the local address space of a
  binary when it is being executed.
  
  With ldd this is shown before execution as
  
  $ ldd oninit
   linux-vdso.so.1 =>  (0x00007fffb7bfe000)
   libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fd2af984000)
  ...
  
  For a running process a /proc/PID/maps output will show
  
  ...
  7fff995fe000-7fff99600000 r-xp 7fff995fe000 00:00 0
          [vdso]
  ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0
          [vsyscall]
  
  The addresses will depend on the system you are using.
  
  This object "linux-vdso.so.1" has no associated filename of a
  shared library residing in the filesystem, because it will
  implicitly be provided by the Linux kernel. In earlier Linux
  versions linux-vdso.so.1 was named linux-gate.so.1.
  
  When this vdso is visible in the address space the startup of
  IDS is printing a warning like
  
   Warning: pid 19160: cannot load NULL library name at address
  0x99efe000
  
  for this shared object in the instance message logfile (the
  address will vary).
  
  Before using a version with APAR IC64908 fixed a message like
  
   pid 9284: can't get real path of
  
  is given for the same reason.
  
  If the vdso object appears in the ldd or /proc/PID/maps output
  this warning can safely be ignored.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Linux users, where VDSO is enabled                       *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * At startup on Linux with VDSO enabled, customers can see a   *
  * warning that server is unable to load some NULL library.     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 11.50.xC7 and above.                              *
  ****************************************************************
  

Problem conclusion

• By default such warnings will not be displayed, unless an
  undocumented env variable IFX_SYM_DEBUG is set.
  Fix applied in IDS.11.50.xC7.
  

Temporary fix

Comments

APAR Information

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

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

Fix information

• Fixed component name

  IBM IDS ENTRP E

• Fixed component ID

  5724L2304

Applicable component levels

• RB15 PSY

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