https://github.com/python/cpython/commit/9c08f40a613d9aee78de4ce4ec3e125d1496d148
commit: 9c08f40a613d9aee78de4ce4ec3e125d1496d148
branch: main
author: Sam Gross <[email protected]>
committer: colesbury <[email protected]>
date: 2024-07-09T12:11:43-04:00
summary:
gh-117657: Fix TSAN races in setobject.c (#121511)
The `used` field must be written using atomic stores because `set_len`
and iterators may access the field concurrently without holding the
per-object lock.
files:
M Objects/setobject.c
M Tools/tsan/suppressions_free_threading.txt
diff --git a/Objects/setobject.c b/Objects/setobject.c
index eb0c404bf6b8e0..5d7ad395d08c90 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -184,14 +184,14 @@ set_add_entry(PySetObject *so, PyObject *key, Py_hash_t
hash)
found_unused_or_dummy:
if (freeslot == NULL)
goto found_unused;
- so->used++;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, so->used + 1);
freeslot->key = key;
freeslot->hash = hash;
return 0;
found_unused:
so->fill++;
- so->used++;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, so->used + 1);
entry->key = key;
entry->hash = hash;
if ((size_t)so->fill*5 < mask*3)
@@ -357,7 +357,7 @@ set_discard_entry(PySetObject *so, PyObject *key, Py_hash_t
hash)
old_key = entry->key;
entry->key = dummy;
entry->hash = -1;
- so->used--;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, so->used - 1);
Py_DECREF(old_key);
return DISCARD_FOUND;
}
@@ -397,7 +397,7 @@ set_empty_to_minsize(PySetObject *so)
{
memset(so->smalltable, 0, sizeof(so->smalltable));
so->fill = 0;
- so->used = 0;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, 0);
so->mask = PySet_MINSIZE - 1;
so->table = so->smalltable;
so->hash = -1;
@@ -615,7 +615,7 @@ set_merge_lock_held(PySetObject *so, PyObject *otherset)
}
}
so->fill = other->fill;
- so->used = other->used;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, other->used);
return 0;
}
@@ -624,7 +624,7 @@ set_merge_lock_held(PySetObject *so, PyObject *otherset)
setentry *newtable = so->table;
size_t newmask = (size_t)so->mask;
so->fill = other->used;
- so->used = other->used;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, other->used);
for (i = other->mask + 1; i > 0 ; i--, other_entry++) {
key = other_entry->key;
if (key != NULL && key != dummy) {
@@ -678,7 +678,7 @@ set_pop_impl(PySetObject *so)
key = entry->key;
entry->key = dummy;
entry->hash = -1;
- so->used--;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(so->used, so->used - 1);
so->finger = entry - so->table + 1; /* next place to start */
return key;
}
@@ -1173,7 +1173,9 @@ set_swap_bodies(PySetObject *a, PySetObject *b)
Py_hash_t h;
t = a->fill; a->fill = b->fill; b->fill = t;
- t = a->used; a->used = b->used; b->used = t;
+ t = a->used;
+ FT_ATOMIC_STORE_SSIZE_RELAXED(a->used, b->used);
+ FT_ATOMIC_STORE_SSIZE_RELAXED(b->used, t);
t = a->mask; a->mask = b->mask; b->mask = t;
u = a->table;
diff --git a/Tools/tsan/suppressions_free_threading.txt
b/Tools/tsan/suppressions_free_threading.txt
index 534a0cedb743dd..fb97bdc128a4e1 100644
--- a/Tools/tsan/suppressions_free_threading.txt
+++ b/Tools/tsan/suppressions_free_threading.txt
@@ -30,8 +30,6 @@ race_top:assign_version_tag
race_top:insertdict
race_top:lookup_tp_dict
race_top:new_reference
-# https://gist.github.com/colesbury/d13d033f413b4ad07929d044bed86c35
-race_top:set_discard_entry
race_top:_PyDict_CheckConsistency
race_top:_Py_dict_lookup_threadsafe
race_top:_multiprocessing_SemLock_acquire_impl
@@ -41,7 +39,6 @@ race_top:insert_to_emptydict
race_top:insertdict
race_top:list_get_item_ref
race_top:make_pending_calls
-race_top:set_add_entry
race_top:_Py_slot_tp_getattr_hook
race_top:add_threadstate
race_top:dump_traceback
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