Merged revisions 60143-60149 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r60143 | georg.brandl | 2008-01-20 15:50:05 +0100 (Sun, 20 Jan 2008) | 3 lines

  Switch mmap from old Py_FindMethod to new PyObject_GenericGetAttr attribute access.
  Fixes #1087735.
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  r60145 | georg.brandl | 2008-01-20 20:40:58 +0100 (Sun, 20 Jan 2008) | 2 lines

  Add blurb about executable scripts on Windows. #760657.
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  r60146 | georg.brandl | 2008-01-20 20:48:40 +0100 (Sun, 20 Jan 2008) | 2 lines

  #1219903: fix tp_richcompare docs.
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  r60147 | georg.brandl | 2008-01-20 22:10:08 +0100 (Sun, 20 Jan 2008) | 2 lines

  Fix markup.
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  r60148 | gregory.p.smith | 2008-01-21 08:11:11 +0100 (Mon, 21 Jan 2008) | 14 lines

  Provide a sanity check during PyThreadState_DeleteCurrent() and
  PyThreadState_Delete() to avoid an infinite loop when the tstate list
  is messed up and has somehow becomes circular and does not contain the
  current thread.

  I don't know how this happens but it does, *very* rarely.  On more than
  one hardware platform.  I have not been able to reproduce it manually.

  Attaching to a process where its happening: it has always been in an
  infinite loop over a single element tstate list that is not the tstate
  we're looking to delete.  It has been in t_bootstrap()'s call to
  PyThreadState_DeleteCurrent() as a pthread is exiting.
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  r60149 | georg.brandl | 2008-01-21 11:24:59 +0100 (Mon, 21 Jan 2008) | 2 lines

  #1269: fix a bug in pstats.add_callers() and add a unit test file for pstats.
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1 files changed, 10 insertions, 0 deletions

diff --git a/Python/pystate.c b/Python/pystate.c
index 030138d..a4d493f 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -242,6 +242,7 @@ tstate_delete_common(PyThreadState *tstate)
 {
 	PyInterpreterState *interp;
 	PyThreadState **p;
+	PyThreadState *prev_p = NULL;
 	if (tstate == NULL)
 		Py_FatalError("PyThreadState_Delete: NULL tstate");
 	interp = tstate->interp;
@@ -254,6 +255,15 @@ tstate_delete_common(PyThreadState *tstate)
 				"PyThreadState_Delete: invalid tstate");
 		if (*p == tstate)
 			break;
+		if (*p == prev_p)
+			Py_FatalError(
+				"PyThreadState_Delete: small circular list(!)"
+                                " and tstate not found.");
+		prev_p = *p;
+		if ((*p)->next == interp->tstate_head)
+			Py_FatalError(
+				"PyThreadState_Delete: circular list(!) and"
+                                " tstate not found.");
 	}
 	*p = tstate->next;
 	HEAD_UNLOCK();