IV63502: HANG UNDER SOME CIRCUMSTANCES WHEN A C++ DTOR UNLOADS LIBRARIES.APPLIES TO AIX 7100-04

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Error Description:
  Two threads could enter a deadlock  and prevent process
  exit when:
  
  Thread A:
    Calls exit()-> which in turn calls DTOR of a
    static object-> which in turn notifies threadB  that
    unloads yet another library.
    Then threadA waits for a semaphore notification from
    threadB.
  
  Two threads will be seen deadlocked with the
  following stack trace( these are actual stack traces
  from a test case that recreates the problem)
  
  First thread(B)
  ==========
  _global_lock_common(??, ??, ??) at 0x90000000053c83c
  _rec_mutex_lock(m = 0x09001000a0f32130), line 399 in
  "rec_mutex.c"
  terminateAndUnload(??) at 0x90000000168ad90
  dlclose(handle = 0x0000000000000003), line 650 in
  "dlfcn.c"
  func(x_void_ptr = (nil)), line 34 in "CPlusPlusClass.C"
  
  Another thread ( A)
  ==========
  _event_sleep(??, ??, ??, ??, ??, ??) at 0x900000000550844
  _event_wait(??, ??) at 0x900000000551344
  _cond_wait_local(??, ??, ??) at 0x90000000055f81c
  _cond_wait(??, ??, ??) at 0x90000000055fe08
  pthread_cond_wait(??, ??) at 0x900000000560a5c
  waitForResponse(), line 27 in "responder.c"
  CPlusPlusClass::~CPlusPlusClass()(this =
  0x09001000a1099658, __dtorFlags = 2), line 62 in
  "CPlusPlusClass.C"
  __srterm__0()(), line 78 in "CPlusPlusClass.C"
  __sterm80000000_x_2fhome_2fanandd_2ftester_2fCPlusPlusCla
  ss_2eC()(), line 55 in "CPlusPlusClass.C"
  __catchThrownException() at 0x9000000005d5a80
  terminate_one_library(??, ??) at 0x900000001689630
  __run_final_dtors() at 0x90000000168722c
  __C_runtime_termination() at 0x10000064c
  exit(??) at 0x900000001582a80
  CPlusPlusClass::foo()(this = 0x09001000a1099658), line
  117 in "CPlusPlusClass.C"
  main(), line 5 in "Main.C"
  

Local fix

Problem summary

• Customer may see deadlock if registration order of
   run_final_dtors()" as an atexit() function has changed.
  

Problem conclusion

• Solution is to avoid deadlock even if the registration order of
  run_final_dtors()" as an atexit() function is changed by
  running real run_final_dtors only at the end.
  

Temporary fix

Comments

APAR Information

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

  IV63130

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

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U871299

     UP15/11/22 I 1000