mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-31 05:58:33 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 7

bpo-30341: Improve _PyTrash_thread_destroy_chain() a little bit (#1545)

Browse source 
* add a comment about why we need to increase trash_delete_nesting
* move increase and decrese outside of the loop
This commit is contained in:
Xiang Zhang 2017-05-13 13:36:14 +08:00 • committed by GitHub
parent 8619c5417c
commit a66f9c6bb1
2 changed files with 16 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

17
Objects/object.c
View file

@ -2093,6 +2093,19 @@ void
_PyTrash_thread_destroy_chain(void)
{
PyThreadState *tstate = PyThreadState_GET();
/* We need to increase trash_delete_nesting here, otherwise,
_PyTrash_thread_destroy_chain will be called recursively
and then possibly crash. An example that may crash without
increase:
N = 500000 # need to be large enough
ob = object()
tups = [(ob,) for i in range(N)]
for i in range(49):
tups = [(tup,) for tup in tups]
del tups
*/
assert(tstate->trash_delete_nesting == 0);
++tstate->trash_delete_nesting;
while (tstate->trash_delete_later) {
PyObject *op = tstate->trash_delete_later;
destructor dealloc = Py_TYPE(op)->tp_dealloc;
@ -2107,10 +2120,10 @@ _PyTrash_thread_destroy_chain(void)
* up distorting allocation statistics.
*/
assert(op->ob_refcnt == 0);
++tstate->trash_delete_nesting;
(*dealloc)(op);
--tstate->trash_delete_nesting;
assert(tstate->trash_delete_nesting == 1);
}
--tstate->trash_delete_nesting;
}
#ifndef Py_TRACE_REFS