IV40257: KSH93 BUILTIN CD MEMORY LEAK IN SUBSHELL APPLIES TO AIX 6100-07

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When using the builtin cd in a ksh93 subshell and the cd
  change to a directory different from the current
  directory
  of the parent, a memory leak occurs.
  The problem is seen using the following example :
  #!/bin/ksh93
  mkdir /home/test 2>/dev/null
  cd /home/test
  integer i=0
  while [[ $i -lt 200 ]] ; do
    text=$(cd /tmp; exit -1)
    i=i+1
  done  2>/dev/null
  ps avg|grep $$
  i=0
  while [[ $i -lt 200 ]] ; do
    text=$(cd /tmp; exit -1)
    i=i+1
  done 2>/dev/null
  ps avg|grep $$
  
  The two ps avg outputs will show memory growth of the
  ksh93 process.
  

Local fix

• 1/If the subshell return 0 the problem doesn't exhibit.
  2/If we move the builtin cd outside of the subshell the
  problem doesn't exhibit either, but then the current
  working directory need to be restored after the subshell
  returns
  from the example replace :
    text=$(cd /tmp; exit -1)
  by :
  cd /tmp
    text=$(exit -1)
  cd -
  Note : the exit is used here for simplification it might
  be replaced by any command that does not return 0.
  3/ If we replace the builtin "cd" in the subshell by the
  /usr/bin/cd command, the problem doesn't exhibit either.
  from the example replace :
    text=$(cd /tmp; exit -1)
  by :
    text=$(/usr/bin/cd /tmp; exit -1)
  

Problem summary

• When using the builtin cd in a ksh93 subshell and the cd
  change to a directory different from the current
  directory of the parent, a memory leak occurs.
  

Problem conclusion

• Code changes has been done to free the memory at relevant
  places.
  

Temporary fix

Comments

• 6100-07 - use AIX APAR IV40257
  6100-08 - use AIX APAR IV57798
  6100-09 - use AIX APAR IV54769
  6100-09 - use AIX APAR IV54769
  6100-09 - use AIX APAR IV54769
  7100-01 - use AIX APAR IV57497
  7100-02 - use AIX APAR IV56943
  7100-03 - use AIX APAR IV54628
  7100-04 - use AIX APAR IV54614
  

APAR Information

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

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

  IV54614 IV54628 IV54769 IV56943 IV57497 IV57798

Fix information

• Fixed component name

  AIX 610 STD EDI

• Fixed component ID

  5765G6200

Applicable component levels

• R610 PSY U864167

     UP14/08/11 I 1000

PTF to Fileset Mapping

• U864167 bos.rte.shell 6.1.7.22