Fixed new seemingly random segfaults, by moving the initialization of

delstr from initgc() into collect().  initgc() isn't called unless the
user explicitly imports gc, so can be used only for initialization of
user-visible module features; delstr needs to be initialized for proper
internal operation, whether or not gc is explicitly imported.

Bugfix candidate?  I don't know whether the new bug was backported to
2.2 already.

diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 659ee038100b88374c4c2269605e476add8972ca..10a90b14f54e7e14f06f8327ae3b90041b58a4ac 100644 (file)
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -59,8 +59,8 @@ static PyObject *garbage;
 /* Python string to use if unhandled exception occurs */
 static PyObject *gc_str;
 
-/* Python string used to looked for __del__ attribute. */
-static PyObject *delstr;
+/* Python string used to look for __del__ attribute. */
+static PyObject *delstr = NULL;
 
 /* set for debugging information */
 #define DEBUG_STATS            (1<<0) /* print collection statistics */
@@ -369,7 +369,7 @@ move_finalizers(PyGC_Head *unreachable, PyGC_Head *collectable,
                        Py_INCREF(op);
                        finalizer = PyObject_HasAttr(op, delstr);
                        if (op->ob_refcnt == 1) {
-                               /* The object will be deallocated. 
+                               /* The object will be deallocated.
                                   Nothing left to do.
                                 */
                                Py_DECREF(op);
@@ -525,6 +525,12 @@ collect(int generation)
        PyGC_Head finalizers;
        PyGC_Head *gc;
 
+       if (delstr == NULL) {
+               delstr = PyString_InternFromString("__del__");
+               if (delstr == NULL)
+                       Py_FatalError("gc couldn't allocate \"__del__\"");
+       }
+
        if (debug & DEBUG_STATS) {
                PySys_WriteStderr("gc: collecting generation %d...\n",
                                  generation);
@@ -578,7 +584,7 @@ collect(int generation)
         * finalizers can't safely be deleted.  Python programmers should take
         * care not to create such things.  For Python, finalizers means
         * instance objects with __del__ methods.
-        * 
+        *
         * Move each object into the collectable set or the finalizers set.
         * It's possible that a classic class with a getattr() hook will
         * be revived or deallocated in this step.
@@ -877,7 +883,7 @@ gc_get_referrents(PyObject *self, PyObject *args)
        int i;
        PyObject *result = PyList_New(0);
        for (i = 0; i < PyTuple_GET_SIZE(args); i++) {
-               PyObject *obj = PyTuple_GET_ITEM(args, i); 
+               PyObject *obj = PyTuple_GET_ITEM(args, i);
                traverseproc traverse = obj->ob_type->tp_traverse;
                if (!traverse)
                        continue;
@@ -969,9 +975,6 @@ initgc(void)
        PyObject *m;
        PyObject *d;
 
-       delstr = PyString_InternFromString("__del__");
-       if (!delstr)
-               return;
        m = Py_InitModule4("gc",
                              GcMethods,
                              gc__doc__,