IZ93224: SEGFAULT WITH CLEAR() IN HASH MAP/SET TABLE

May 2012 PTF for XL C/C++ for AIX, V10.1
January 2013 PTF for XL C/C++ for AIX, V10.1
XL C/C++ for AIX Fix Pack 18 (July 2013 PTF) for 10.1
XL C/C++ for AIX Fix Pack 19 (October 2013 PTF) for 10.1
XL C/C++ for AIX Fix Pack 21 (October 2015 PTF) for 10.1
May 2011 PTF for XL C/C++ for AIX, V10.1
October 2011 PTF for XL C/C++ for AIX, V10.1
February 2012 PTF for XL C/C++ for AIX, V10.1
September 2012 PTF for XL C/C++ for AIX, V10.1
XL C/C++ for AIX Fix Pack 20 (October 2014 PTF) for 10.1

APAR status

• Closed as program error.

Error description

• The following test case segfaults at runtime:
  
  ===== COMPILE COMMAND:
  xlC_r -o tc tc.cpp -q64 -D__IBMCPP_TR1__
  
  ===== TESTCASE:
  $ cat tc.cpp
  #include <iostream>
  #include <memory>
  #include <unordered_set>
  
  int main()
  {
          std::auto_ptr<std::tr1::unordered_set<unsigned int> >
  container(new std::tr1::unordered_set<unsigned int>());
          for (unsigned int i = 1; i < 5; i++)
          {
                  container->clear();
                  for (unsigned int j = 0; j < 50*i; j++)
                          container->insert(rand()%100000);
                  std::cout << "i =" << i << std::endl;
          }
  }
  
  
  
  
  
  ===== ACTUAL OUTPUT:
  $ ./tc
  i =1
  Segmentation fault (core dumped)
  
  
  ===== EXPECTED OUTPUT:
  Should not segfault.
  

Local fix

• N/A
  

Problem summary

• USERS AFFECTED:
  Users who use clear() and in some insertion cases in TR1
  set/map and multi set/map maybe affected by this issue.
  
  PROBLEM DESCRIPTION:
  Rehashing can cause buckets to hash to uninitialized memory
  causing applications to segfault at runtime.
  

Problem conclusion

• The compiler has been fixed to address the issue in the clear()
  function.
  

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:

  IZ93241 IZ96365

Fix information

• Fixed component name

  XL C++ AIX

• Fixed component ID

  5724U8100

Applicable component levels