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bpo-40602: _Py_hashtable_set() reports rehash failure (GH-20077)

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If _Py_hashtable_set() fails to grow the hash table (rehash), it now
fails rather than ignoring the error.
This commit is contained in:
Victor Stinner 2020-05-14 22:44:32 +02:00 • committed by GitHub
parent ce21cfca7b
commit d2dc827d16
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 27 additions and 15 deletions
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28
Python/hashtable.c
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@ -60,7 +60,7 @@
((_Py_hashtable_entry_t *)_Py_SLIST_ITEM_NEXT(ENTRY))
/* Forward declaration */
static void hashtable_rehash(_Py_hashtable_t *ht);
static int hashtable_rehash(_Py_hashtable_t *ht);
static void
_Py_slist_init(_Py_slist_t *list)
@ -198,6 +198,7 @@ _Py_hashtable_steal(_Py_hashtable_t *ht, const void *key)
ht->alloc.free(entry);
if ((float)ht->nentries / (float)ht->nbuckets < HASHTABLE_LOW) {
// Ignore failure: error cannot be reported to the caller
hashtable_rehash(ht);
}
return value;
@ -228,13 +229,17 @@ _Py_hashtable_set(_Py_hashtable_t *ht, const void *key, void *value)
entry->key = (void *)key;
entry->value = value;
ht->nentries++;
if ((float)ht->nentries / (float)ht->nbuckets > HASHTABLE_HIGH) {
if (hashtable_rehash(ht) < 0) {
ht->nentries--;
ht->alloc.free(entry);
return -1;
}
}
size_t index = entry->key_hash & (ht->nbuckets - 1);
_Py_slist_prepend(&ht->buckets[index], (_Py_slist_item_t*)entry);
ht->nentries++;
if ((float)ht->nentries / (float)ht->nbuckets > HASHTABLE_HIGH) {
hashtable_rehash(ht);
}
return 0;
}
@ -271,19 +276,19 @@ _Py_hashtable_foreach(_Py_hashtable_t *ht,
}
static void
static int
hashtable_rehash(_Py_hashtable_t *ht)
{
size_t new_size = round_size((size_t)(ht->nentries * HASHTABLE_REHASH_FACTOR));
if (new_size == ht->nbuckets) {
return;
return 0;
}
size_t buckets_size = new_size * sizeof(ht->buckets[0]);
_Py_slist_t *new_buckets = ht->alloc.malloc(buckets_size);
if (new_buckets == NULL) {
/* memory allocation failed */
return;
return -1;
}
memset(new_buckets, 0, buckets_size);
@ -303,6 +308,7 @@ hashtable_rehash(_Py_hashtable_t *ht)
ht->alloc.free(ht->buckets);
ht->nbuckets = new_size;
ht->buckets = new_buckets;
return 0;
}
@ -388,7 +394,9 @@ _Py_hashtable_clear(_Py_hashtable_t *ht)
_Py_slist_init(&ht->buckets[i]);
}
ht->nentries = 0;
hashtable_rehash(ht);
// Ignore failure: clear function is not expected to fail
// because of a memory allocation failure.
(void)hashtable_rehash(ht);
}