IC75819: THREAD STACK OVERFLOW AND MEMORY CORRUPTION WHEN GL_USEGLU IS SET

APAR status

• Closed as program error.

Error description

• When environment variable GL_USEGLU is set, a different dynamic
  library
  is loaded to handle UTF8 locales. This library needs more stack
  space than normally. Occasionally the server checks if there is
  more stack
  space left than 32 KB plus some stack margin value (a couple of
  KB). But
  this check is not performed on every function call. This can
  result in
  stack overflow if a call to the GLU library is made.
  
  If the stack check is done on a 32 KB stack, it will always
  result in
  the allocation of a new stack visible in onstat -g stk. For this
  reason,
  starting with a 32 KB stack makes no sense and is dangerous.
  
  The minimum allowed thread stack size when GL_USEGLU is set
  should be at
  least 64 KB. In 32 bit ports of IDS, the default in the onconfig
  file
  currently is only 32 KB.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users.                                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * When environment variable GL_USEGLU is set, a different      *
  * dynamic library is loaded to handle UTF8 locales. This       *
  * library needs more stack space than                          *
  * normally. Occasionally the server checks if there is more    *
  * stack space left than 32 KB plus some stack margin value (a  *
  * couple of KB) but this check is                              *
  * not performed on every function call. This can result in     *
  * stack overflow if a call to the GLU library is made.         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix 11.50.xC9 when available.                *
  ****************************************************************
  

Problem conclusion

• The problem is fixed in Informix 11.50.xC9.
  

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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