Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

gh-117657: Fix TSan race in _PyDict_CheckConsistency #121551

Merged
merged 1 commit into from
Jul 10, 2024
Merged

gh-117657: Fix TSan race in _PyDict_CheckConsistency #121551

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 15 additions & 9 deletions Objects/dictobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -165,16 +165,15 @@ ASSERT_DICT_LOCKED(PyObject *op)
#define STORE_INDEX(keys, size, idx, value) _Py_atomic_store_int##size##_relaxed(&((int##size##_t*)keys->dk_indices)[idx], (int##size##_t)value);
#define ASSERT_OWNED_OR_SHARED(mp) \
assert(_Py_IsOwnedByCurrentThread((PyObject *)mp) || IS_DICT_SHARED(mp));
#define LOAD_KEYS_NENTRIES(d)

#define LOCK_KEYS_IF_SPLIT(keys, kind) \
if (kind == DICT_KEYS_SPLIT) { \
LOCK_KEYS(dk); \
LOCK_KEYS(keys); \
}

#define UNLOCK_KEYS_IF_SPLIT(keys, kind) \
if (kind == DICT_KEYS_SPLIT) { \
UNLOCK_KEYS(dk); \
UNLOCK_KEYS(keys); \
}

static inline Py_ssize_t
Expand Down Expand Up @@ -208,7 +207,7 @@ set_values(PyDictObject *mp, PyDictValues *values)
#define INCREF_KEYS(dk) _Py_atomic_add_ssize(&dk->dk_refcnt, 1)
// Dec refs the keys object, giving the previous value
#define DECREF_KEYS(dk) _Py_atomic_add_ssize(&dk->dk_refcnt, -1)
#define LOAD_KEYS_NENTIRES(keys) _Py_atomic_load_ssize_relaxed(&keys->dk_nentries)
#define LOAD_KEYS_NENTRIES(keys) _Py_atomic_load_ssize_relaxed(&keys->dk_nentries)

#define INCREF_KEYS_FT(dk) dictkeys_incref(dk)
#define DECREF_KEYS_FT(dk, shared) dictkeys_decref(_PyInterpreterState_GET(), dk, shared)
Expand All @@ -234,7 +233,7 @@ static inline void split_keys_entry_added(PyDictKeysObject *keys)
#define STORE_SHARED_KEY(key, value) key = value
#define INCREF_KEYS(dk) dk->dk_refcnt++
#define DECREF_KEYS(dk) dk->dk_refcnt--
#define LOAD_KEYS_NENTIRES(keys) keys->dk_nentries
#define LOAD_KEYS_NENTRIES(keys) keys->dk_nentries
#define INCREF_KEYS_FT(dk)
#define DECREF_KEYS_FT(dk, shared)
#define LOCK_KEYS_IF_SPLIT(keys, kind)
Expand Down Expand Up @@ -689,10 +688,15 @@ _PyDict_CheckConsistency(PyObject *op, int check_content)
int splitted = _PyDict_HasSplitTable(mp);
Py_ssize_t usable = USABLE_FRACTION(DK_SIZE(keys));

// In the free-threaded build, shared keys may be concurrently modified,
// so use atomic loads.
Py_ssize_t dk_usable = FT_ATOMIC_LOAD_SSIZE_ACQUIRE(keys->dk_usable);
Py_ssize_t dk_nentries = FT_ATOMIC_LOAD_SSIZE_ACQUIRE(keys->dk_nentries);

CHECK(0 <= mp->ma_used && mp->ma_used <= usable);
CHECK(0 <= keys->dk_usable && keys->dk_usable <= usable);
CHECK(0 <= keys->dk_nentries && keys->dk_nentries <= usable);
CHECK(keys->dk_usable + keys->dk_nentries <= usable);
CHECK(0 <= dk_usable && dk_usable <= usable);
CHECK(0 <= dk_nentries && dk_nentries <= usable);
CHECK(dk_usable + dk_nentries <= usable);

if (!splitted) {
/* combined table */
Expand All @@ -709,6 +713,7 @@ _PyDict_CheckConsistency(PyObject *op, int check_content)
}

if (check_content) {
LOCK_KEYS_IF_SPLIT(keys, keys->dk_kind);
for (Py_ssize_t i=0; i < DK_SIZE(keys); i++) {
Py_ssize_t ix = dictkeys_get_index(keys, i);
CHECK(DKIX_DUMMY <= ix && ix <= usable);
Expand Down Expand Up @@ -764,6 +769,7 @@ _PyDict_CheckConsistency(PyObject *op, int check_content)
CHECK(mp->ma_values->values[index] != NULL);
}
}
UNLOCK_KEYS_IF_SPLIT(keys, keys->dk_kind);
}
return 1;

Expand Down Expand Up @@ -4032,7 +4038,7 @@ dict_equal_lock_held(PyDictObject *a, PyDictObject *b)
/* can't be equal if # of entries differ */
return 0;
/* Same # of entries -- check all of 'em. Exit early on any diff. */
for (i = 0; i < LOAD_KEYS_NENTIRES(a->ma_keys); i++) {
for (i = 0; i < LOAD_KEYS_NENTRIES(a->ma_keys); i++) {
PyObject *key, *aval;
Py_hash_t hash;
if (DK_IS_UNICODE(a->ma_keys)) {
Expand Down
8 changes: 0 additions & 8 deletions Tools/tsan/suppressions_free_threading.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -27,16 +27,8 @@ race_top:_add_to_weak_set
race_top:_in_weak_set
race_top:_PyEval_EvalFrameDefault
race_top:assign_version_tag
race_top:insertdict
race_top:lookup_tp_dict
race_top:new_reference
race_top:_PyDict_CheckConsistency
race_top:_Py_dict_lookup_threadsafe
race_top:_multiprocessing_SemLock_acquire_impl
race_top:dictiter_new
race_top:dictresize
race_top:insert_to_emptydict
race_top:insertdict
race_top:list_get_item_ref
race_top:make_pending_calls
race_top:_Py_slot_tp_getattr_hook
Expand Down
Loading