https://github.com/python/cpython/commit/19d468a3ab1d57c07a4283d67d439908574aa0cc
commit: 19d468a3ab1d57c07a4283d67d439908574aa0cc
branch: main
author: Dino Viehland <[email protected]>
committer: DinoV <[email protected]>
date: 2024-04-30T12:37:38-07:00
summary:
[gh-117657] Fix some issues with TSAN in typeobject (#118249)
Fix some racing reads in typebobject.c
files:
M Include/internal/pycore_pyatomic_ft_wrappers.h
M Objects/typeobject.c
diff --git a/Include/internal/pycore_pyatomic_ft_wrappers.h
b/Include/internal/pycore_pyatomic_ft_wrappers.h
index 83f02c92495b3f..bc6aba56cf9fc7 100644
--- a/Include/internal/pycore_pyatomic_ft_wrappers.h
+++ b/Include/internal/pycore_pyatomic_ft_wrappers.h
@@ -43,6 +43,8 @@ extern "C" {
_Py_atomic_load_uint8_relaxed(&value)
#define FT_ATOMIC_LOAD_UINT16_RELAXED(value) \
_Py_atomic_load_uint16_relaxed(&value)
+#define FT_ATOMIC_LOAD_UINT32_RELAXED(value) \
+ _Py_atomic_load_uint32_relaxed(&value)
#define FT_ATOMIC_STORE_PTR_RELAXED(value, new_value) \
_Py_atomic_store_ptr_relaxed(&value, new_value)
#define FT_ATOMIC_STORE_PTR_RELEASE(value, new_value) \
@@ -55,6 +57,9 @@ extern "C" {
_Py_atomic_store_uint8_relaxed(&value, new_value)
#define FT_ATOMIC_STORE_UINT16_RELAXED(value, new_value) \
_Py_atomic_store_uint16_relaxed(&value, new_value)
+#define FT_ATOMIC_STORE_UINT32_RELAXED(value, new_value) \
+ _Py_atomic_store_uint32_relaxed(&value, new_value)
+
#else
#define FT_ATOMIC_LOAD_PTR(value) value
#define FT_ATOMIC_STORE_PTR(value, new_value) value = new_value
@@ -69,12 +74,15 @@ extern "C" {
#define FT_ATOMIC_STORE_UINT8(value, new_value) value = new_value
#define FT_ATOMIC_LOAD_UINT8_RELAXED(value) value
#define FT_ATOMIC_LOAD_UINT16_RELAXED(value) value
+#define FT_ATOMIC_LOAD_UINT32_RELAXED(value) value
#define FT_ATOMIC_STORE_PTR_RELAXED(value, new_value) value = new_value
#define FT_ATOMIC_STORE_PTR_RELEASE(value, new_value) value = new_value
#define FT_ATOMIC_STORE_UINTPTR_RELEASE(value, new_value) value = new_value
#define FT_ATOMIC_STORE_SSIZE_RELAXED(value, new_value) value = new_value
#define FT_ATOMIC_STORE_UINT8_RELAXED(value, new_value) value = new_value
#define FT_ATOMIC_STORE_UINT16_RELAXED(value, new_value) value = new_value
+#define FT_ATOMIC_STORE_UINT32_RELAXED(value, new_value) value = new_value
+
#endif
#ifdef __cplusplus
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 50efbb6e182df0..ec19a3d461f623 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -43,7 +43,8 @@ class object "PyObject *" "&PyBaseObject_Type"
& ((1 << MCACHE_SIZE_EXP) - 1))
#define MCACHE_HASH_METHOD(type, name) \
- MCACHE_HASH((type)->tp_version_tag, ((Py_ssize_t)(name)) >> 3)
+ MCACHE_HASH(FT_ATOMIC_LOAD_UINT32_RELAXED((type)->tp_version_tag), \
+ ((Py_ssize_t)(name)) >> 3)
#define MCACHE_CACHEABLE_NAME(name) \
PyUnicode_CheckExact(name) && \
PyUnicode_IS_READY(name) && \
@@ -907,7 +908,7 @@ type_modified_unlocked(PyTypeObject *type)
}
type->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;
- type->tp_version_tag = 0; /* 0 is not a valid version tag */
+ FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag, 0); /* 0 is not a
valid version tag */
if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
// This field *must* be invalidated if the type is modified (see the
// comment on struct _specialization_cache):
@@ -984,7 +985,7 @@ type_mro_modified(PyTypeObject *type, PyObject *bases) {
clear:
assert(!(type->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN));
type->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;
- type->tp_version_tag = 0; /* 0 is not a valid version tag */
+ FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag, 0); /* 0 is not a
valid version tag */
if (PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
// This field *must* be invalidated if the type is modified (see the
// comment on struct _specialization_cache):
@@ -1020,7 +1021,8 @@ assign_version_tag(PyInterpreterState *interp,
PyTypeObject *type)
/* We have run out of version numbers */
return 0;
}
- type->tp_version_tag = NEXT_GLOBAL_VERSION_TAG++;
+ FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag,
+ NEXT_GLOBAL_VERSION_TAG++);
assert (type->tp_version_tag <= _Py_MAX_GLOBAL_TYPE_VERSION_TAG);
}
else {
@@ -1029,7 +1031,8 @@ assign_version_tag(PyInterpreterState *interp,
PyTypeObject *type)
/* We have run out of version numbers */
return 0;
}
- type->tp_version_tag = NEXT_VERSION_TAG(interp)++;
+ FT_ATOMIC_STORE_UINT32_RELAXED(type->tp_version_tag,
+ NEXT_VERSION_TAG(interp)++);
assert (type->tp_version_tag != 0);
}
@@ -5085,7 +5088,9 @@ _PyType_Lookup(PyTypeObject *type, PyObject *name)
// synchronize-with other writing threads by doing an acquire load on the
sequence
while (1) {
int sequence = _PySeqLock_BeginRead(&entry->sequence);
- if (_Py_atomic_load_uint32_relaxed(&entry->version) ==
type->tp_version_tag &&
+ uint32_t entry_version =
_Py_atomic_load_uint32_relaxed(&entry->version);
+ uint32_t type_version =
_Py_atomic_load_uint32_relaxed(&type->tp_version_tag);
+ if (entry_version == type_version &&
_Py_atomic_load_ptr_relaxed(&entry->name) == name) {
assert(_PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG));
OBJECT_STAT_INC_COND(type_cache_hits, !is_dunder_name(name));
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