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authorSerhiy Storchaka <storchaka@gmail.com>2017-01-12 17:42:20 (GMT)
committerSerhiy Storchaka <storchaka@gmail.com>2017-01-12 17:42:20 (GMT)
commit617c7753ce010617b45ae3bfa53a90c07b51510a (patch)
tree974d15dcc99f3504be149746e9b4069e5a2db6cc /Objects/dictobject.c
parent798ad2742b6523250e5477557e3cc2588d6e6475 (diff)
parent42e1ea9a10aa6c3df40af3b7561d6251c8e2ac9c (diff)
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Issue #28969: Fixed race condition in C implementation of functools.lru_cache.
KeyError could be raised when cached function with full cache was simultaneously called from differen threads with the same uncached arguments.
Diffstat (limited to 'Objects/dictobject.c')
-rw-r--r--Objects/dictobject.c31
1 files changed, 23 insertions, 8 deletions
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index baef589..9950f50 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -1817,9 +1817,8 @@ PyDict_Next(PyObject *op, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue)
/* Internal version of dict.pop(). */
PyObject *
-_PyDict_Pop(PyObject *dict, PyObject *key, PyObject *deflt)
+_PyDict_Pop_KnownHash(PyObject *dict, PyObject *key, Py_hash_t hash, PyObject *deflt)
{
- Py_hash_t hash;
Py_ssize_t ix, hashpos;
PyObject *old_value, *old_key;
PyDictKeyEntry *ep;
@@ -1836,12 +1835,6 @@ _PyDict_Pop(PyObject *dict, PyObject *key, PyObject *deflt)
_PyErr_SetKeyError(key);
return NULL;
}
- if (!PyUnicode_CheckExact(key) ||
- (hash = ((PyASCIIObject *) key)->hash) == -1) {
- hash = PyObject_Hash(key);
- if (hash == -1)
- return NULL;
- }
ix = (mp->ma_keys->dk_lookup)(mp, key, hash, &old_value, &hashpos);
if (ix == DKIX_ERROR)
return NULL;
@@ -1878,6 +1871,28 @@ _PyDict_Pop(PyObject *dict, PyObject *key, PyObject *deflt)
return old_value;
}
+PyObject *
+_PyDict_Pop(PyObject *dict, PyObject *key, PyObject *deflt)
+{
+ Py_hash_t hash;
+
+ if (((PyDictObject *)dict)->ma_used == 0) {
+ if (deflt) {
+ Py_INCREF(deflt);
+ return deflt;
+ }
+ _PyErr_SetKeyError(key);
+ return NULL;
+ }
+ if (!PyUnicode_CheckExact(key) ||
+ (hash = ((PyASCIIObject *) key)->hash) == -1) {
+ hash = PyObject_Hash(key);
+ if (hash == -1)
+ return NULL;
+ }
+ return _PyDict_Pop_KnownHash(dict, key, hash, deflt);
+}
+
/* Internal version of dict.from_keys(). It is subclass-friendly. */
PyObject *
_PyDict_FromKeys(PyObject *cls, PyObject *iterable, PyObject *value)