[Python-Dev] debugging test_importlib.test_bad_traverse - script status is SUCCESS (original) (raw)

Michael aixtools at felt.demon.nl
Tue Sep 18 05:48:53 EDT 2018

On 17/09/2018 09:39, Michael wrote:

I read the discussion related to issue32374. That seems to be sure that other events that could cause the test to fail (i.e., the program executes successfully) are caught early, and/or ignored so that the program fails - and the test succeeds.

After reading below, I would appreciate knowing whether to ask that issue32374 be reopened and the test adjusted so that the test is "SkipIf" AIX? Or, something else? I'll work on something else, but I do not want to guess the current intent of this test module.

+++++++

In: Modules/_testmultiphase.c - found where AIX and Linux differ in their response to accessing a NULL pointer, in this case m_state->integer

  +624  static int   +625  bad_traverse(PyObject *self, visitproc visit, void *arg) {   +626      testmultiphase_state *m_state;   +627     FILE err = fopen("/tmp/err","a");   +628   +629      m_state = PyModule_GetState(self);   +630   +631  fprintf(err,"%s:%d\n", FILE,LINE); fflush(err);   +632  fprintf(err, "m_state:08%lx &m_state->integer:%08lx\n",   +633          m_state, &(m_state->integer));   +634  fclose(err);   +635      Py_VISIT(m_state->integer);   +636  /   +637  #define Py_VISIT(op)   +638      do {   +639          if (m_state->integer) {   +640              int vret = visit((PyObject *)(m_state->integer), arg);   +641              if (vret) {   +642                  return vret;   +643              }   +644          }   +645      } while (0);   +646  */   +647      return 0;   +648  }

The "m_state" and m_state->integer values are identical, but the response is not.

root at x066:[/data/prj/python/git]uname AIX /data/prj/python/git/python3-3.8/Modules/_testmultiphase.c:631 m_state:080 &m_state->integer:00000000

root at x074:/data/prj/python/git# uname Linux /data/prj/python/git/Python3-3.8.0/Modules/_testmultiphase.c:631 m_state:080 &m_state->integer:00000000

++++++ Test program to demonstrate +++++++ AIX does not segmentfault on access of a NULL pointer ++++++++++++++++++++++++++++++++++++++++++ root at x074:/data/prj/python/git# cat nullpr.c #include<stdio.h> main() {         int *vpt = NULL;

fprintf(stdout, "vpt = %08lx\n", vpt); if (*vpt)         fprintf(stdout,"True\n"); else         fprintf(stdout,"False\n"); }

root at x074:/data/prj/python/git# rm -f nullpr; make nullpr; ./nullpr make: Warning: File 'nullpr.c' has modification time 387 s in the future cc     nullpr.c   -o nullpr nullpr.c:2:1: warning: return type defaults to 'int' [-Wimplicit-int]  main()  ^ make: warning:  Clock skew detected.  Your build may be incomplete. vpt = 00000000 Segmentation fault

++++++++++ AIX does not 'Segmenttation fault' +++++++++++++ root at x066:[/data/prj/python/git]rm -r nullpr; make nullpr; ./nullpr cc     nullpr.c   -o nullpr vpt = 00000000 False

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