From: Sergey B Kirpichev <skirpichev@gmail.com>
Date: Thu, 30 Jul 2026 15:02:59 +0000 (+0300)
Subject: gh-154037: Fix race in the hash(Decimal) (#154045)
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=2f381f5a90474d9dad12e1e4946f348dd4b513bc;p=thirdparty%2FPython%2Fcpython.git

gh-154037: Fix race in the hash(Decimal) (#154045)
---

diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index 6fbce0ed85e6..ac3ffb23248f 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -5935,11 +5935,13 @@ static Py_hash_t
 dec_hash(PyObject *op)
 {
     PyDecObject *self = _PyDecObject_CAST(op);
-    if (self->hash == -1) {
-        self->hash = _dec_hash(self);
-    }
+    Py_hash_t hash = FT_ATOMIC_LOAD_SSIZE_RELAXED(self->hash);
 
-    return self->hash;
+    if (hash == -1) {
+        hash = _dec_hash(self);
+        FT_ATOMIC_STORE_SSIZE_RELAXED(self->hash, hash);
+    }
+    return hash;
 }
 
 /*[clinic input]