gh-112075: Make PyDictKeysObject thread-safe (#114741)

Adds locking for shared PyDictKeysObject's for dictionaries
python · Feb 21, 2024 · 176df09 · 176df09
1 parent 145bc2d
commit 176df09
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Showing 6 changed files with 257 additions and 93 deletions.
diff --git a/Include/cpython/pyatomic.h b/Include/cpython/pyatomic.h
@@ -469,6 +469,9 @@ _Py_atomic_load_ptr_acquire(const void *obj);
 static inline void
 _Py_atomic_store_ptr_release(void *obj, void *value);
 
+static inline void
+_Py_atomic_store_ssize_release(Py_ssize_t *obj, Py_ssize_t value);
+
 static inline void
 _Py_atomic_store_int_release(int *obj, int value);
 
@@ -484,6 +487,9 @@ _Py_atomic_load_uint64_acquire(const uint64_t *obj);
 static inline uint32_t
 _Py_atomic_load_uint32_acquire(const uint32_t *obj);
 
+static inline Py_ssize_t
+_Py_atomic_load_ssize_acquire(const Py_ssize_t *obj);
+
 
 // --- _Py_atomic_fence ------------------------------------------------------
 

diff --git a/Include/cpython/pyatomic_gcc.h b/Include/cpython/pyatomic_gcc.h
@@ -500,6 +500,10 @@ static inline void
 _Py_atomic_store_int_release(int *obj, int value)
 { __atomic_store_n(obj, value, __ATOMIC_RELEASE); }
 
+static inline void
+_Py_atomic_store_ssize_release(Py_ssize_t *obj, Py_ssize_t value)
+{ __atomic_store_n(obj, value, __ATOMIC_RELEASE); }
+
 static inline int
 _Py_atomic_load_int_acquire(const int *obj)
 { return __atomic_load_n(obj, __ATOMIC_ACQUIRE); }
@@ -516,6 +520,10 @@ static inline uint32_t
 _Py_atomic_load_uint32_acquire(const uint32_t *obj)
 { return __atomic_load_n(obj, __ATOMIC_ACQUIRE); }
 
+static inline Py_ssize_t
+_Py_atomic_load_ssize_acquire(const Py_ssize_t *obj)
+{ return __atomic_load_n(obj, __ATOMIC_ACQUIRE); }
+
 // --- _Py_atomic_fence ------------------------------------------------------
 
 static inline void

diff --git a/Include/cpython/pyatomic_msc.h b/Include/cpython/pyatomic_msc.h
@@ -939,6 +939,18 @@ _Py_atomic_store_int_release(int *obj, int value)
 #endif
 }
 
+static inline void
+_Py_atomic_store_ssize_release(Py_ssize_t *obj, Py_ssize_t value)
+{
+#if defined(_M_X64) || defined(_M_IX86)
+    *(Py_ssize_t volatile *)obj = value;
+#elif defined(_M_ARM64)
+    __stlr64((unsigned __int64 volatile *)obj, (unsigned __int64)value);
+#else
+#  error "no implementation of _Py_atomic_store_ssize_release"
+#endif
+}
+
 static inline int
 _Py_atomic_load_int_acquire(const int *obj)
 {
@@ -990,6 +1002,18 @@ _Py_atomic_load_uint32_acquire(const uint32_t *obj)
 #endif
 }
 
+static inline Py_ssize_t
+_Py_atomic_load_ssize_acquire(const Py_ssize_t *obj)
+{
+#if defined(_M_X64) || defined(_M_IX86)
+    return *(Py_ssize_t volatile *)obj;
+#elif defined(_M_ARM64)
+    return (Py_ssize_t)__ldar64((unsigned __int64 volatile *)obj);
+#else
+#  error "no implementation of _Py_atomic_load_ssize_acquire"
+#endif
+}
+
 // --- _Py_atomic_fence ------------------------------------------------------
 
  static inline void

diff --git a/Include/cpython/pyatomic_std.h b/Include/cpython/pyatomic_std.h
@@ -879,6 +879,14 @@ _Py_atomic_store_int_release(int *obj, int value)
                           memory_order_release);
 }
 
+static inline void
+_Py_atomic_store_ssize_release(Py_ssize_t *obj, Py_ssize_t value)
+{
+    _Py_USING_STD;
+    atomic_store_explicit((_Atomic(Py_ssize_t)*)obj, value,
+                          memory_order_release);
+}
+
 static inline int
 _Py_atomic_load_int_acquire(const int *obj)
 {
@@ -908,7 +916,13 @@ _Py_atomic_load_uint32_acquire(const uint32_t *obj)
 {
     _Py_USING_STD;
     return atomic_load_explicit((const _Atomic(uint32_t)*)obj,
-                                memory_order_acquire);
+}
+
+static inline Py_ssize_t
+_Py_atomic_load_ssize_acquire(const Py_ssize_t *obj)
+{
+    _Py_USING_STD;
+    return atomic_load_explicit((const _Atomic(Py_ssize_t)*)obj,
 }
 
 

diff --git a/Include/internal/pycore_dict.h b/Include/internal/pycore_dict.h
@@ -136,6 +136,11 @@ struct _dictkeysobject {
     /* Kind of keys */
     uint8_t dk_kind;
 
+#ifdef Py_GIL_DISABLED
+    /* Lock used to protect shared keys */
+    PyMutex dk_mutex;
+#endif
+
     /* Version number -- Reset to 0 by any modification to keys */
     uint32_t dk_version;
 
@@ -145,6 +150,7 @@ struct _dictkeysobject {
     /* Number of used entries in dk_entries. */
     Py_ssize_t dk_nentries;
 
+
     /* Actual hash table of dk_size entries. It holds indices in dk_entries,
        or DKIX_EMPTY(-1) or DKIX_DUMMY(-2).