commit 351c67416ba4451eb3928fa0b2e933c2f25df1a3
author Jeroen Demeyer <J.Demeyer@UGent.be> Fri May 10 19:21:11 2019 +0200
committer Antoine Pitrou <antoine@python.org> Fri May 10 19:21:10 2019 +0200
tree 5054fe93291fa93533ddd97622f329e96a31847e
parent a2fedd8c910cb5f5b9bd568d6fd44d63f8f5cfa5

bpo-35983: skip trashcan for subclasses (GH-11841)

Add new trashcan macros to deal with a double deallocation that could occur when the `tp_dealloc` of a subclass calls the `tp_dealloc` of a base class and that base class uses the trashcan mechanism.

Patch by Jeroen Demeyer.

Python/hamt.c

diff --git a/Python/hamt.c b/Python/hamt.c
index 67af04c..b3cbf9a 100644
--- a/Python/hamt.c
+++ b/Python/hamt.c
@@ -1176,7 +1176,7 @@
     Py_ssize_t i;
 
     PyObject_GC_UnTrack(self);
-    Py_TRASHCAN_SAFE_BEGIN(self)
+    Py_TRASHCAN_BEGIN(self, hamt_node_bitmap_dealloc)
 
     if (len > 0) {
         i = len;
@@ -1186,7 +1186,7 @@
     }
 
     Py_TYPE(self)->tp_free((PyObject *)self);
-    Py_TRASHCAN_SAFE_END(self)
+    Py_TRASHCAN_END
 }
 
 #ifdef Py_DEBUG
@@ -1584,7 +1584,7 @@
     Py_ssize_t len = Py_SIZE(self);
 
     PyObject_GC_UnTrack(self);
-    Py_TRASHCAN_SAFE_BEGIN(self)
+    Py_TRASHCAN_BEGIN(self, hamt_node_collision_dealloc)
 
     if (len > 0) {
 
@@ -1594,7 +1594,7 @@
     }
 
     Py_TYPE(self)->tp_free((PyObject *)self);
-    Py_TRASHCAN_SAFE_END(self)
+    Py_TRASHCAN_END
 }
 
 #ifdef Py_DEBUG
@@ -1969,14 +1969,14 @@
     Py_ssize_t i;
 
     PyObject_GC_UnTrack(self);
-    Py_TRASHCAN_SAFE_BEGIN(self)
+    Py_TRASHCAN_BEGIN(self, hamt_node_array_dealloc)
 
     for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) {
         Py_XDECREF(self->a_array[i]);
     }
 
     Py_TYPE(self)->tp_free((PyObject *)self);
-    Py_TRASHCAN_SAFE_END(self)
+    Py_TRASHCAN_END
 }
 
 #ifdef Py_DEBUG

Python/traceback.c

diff --git a/Python/traceback.c b/Python/traceback.c
index bd1061e..18bd0bf 100644
--- a/Python/traceback.c
+++ b/Python/traceback.c
@@ -163,11 +163,11 @@
 tb_dealloc(PyTracebackObject *tb)
 {
     PyObject_GC_UnTrack(tb);
-    Py_TRASHCAN_SAFE_BEGIN(tb)
+    Py_TRASHCAN_BEGIN(tb, tb_dealloc)
     Py_XDECREF(tb->tb_next);
     Py_XDECREF(tb->tb_frame);
     PyObject_GC_Del(tb);
-    Py_TRASHCAN_SAFE_END(tb)
+    Py_TRASHCAN_END
 }
 
 static int