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[TD-825] race condtion while free object in cache

This commit is contained in:
Shengliang Guan 2020-07-14 14:33:55 +08:00
parent 4b8428855f
commit 627cdc0749
1 changed files with 7 additions and 8 deletions
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15
src/util/src/tcache.c
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@ -453,21 +453,20 @@ void taosCacheRelease(SCacheObj *pCacheObj, void **data, bool _remove) {
} else { } else {
uDebug("cache:%s, key:%p, %p is released, refcnt:%d", pCacheObj->name, pNode->key, pNode->data, T_REF_VAL_GET(pNode) - 1); uDebug("cache:%s, key:%p, %p is released, refcnt:%d", pCacheObj->name, pNode->key, pNode->data, T_REF_VAL_GET(pNode) - 1);
__cache_wr_lock(pCacheObj);
// NOTE: once refcount is decrease, pNode may be freed by other thread immediately. // NOTE: once refcount is decrease, pNode may be freed by other thread immediately.
int32_t ref = T_REF_DEC(pNode); int32_t ref = T_REF_DEC(pNode);
if (inTrashCan) { if (inTrashCan && (ref == 0)) {
// Remove it if the ref count is 0. // Remove it if the ref count is 0.
// The ref count does not need to load and check again after lock acquired, since ref count can not be increased when // The ref count does not need to load and check again after lock acquired, since ref count can not be increased when
// the node is in trashcan. // the node is in trashcan.
if (ref == 0) { assert(pNode->pTNodeHeader->pData == pNode);
__cache_wr_lock(pCacheObj); taosRemoveFromTrashCan(pCacheObj, pNode->pTNodeHeader);
assert(pNode->pTNodeHeader->pData == pNode);
taosRemoveFromTrashCan(pCacheObj, pNode->pTNodeHeader);
__cache_unlock(pCacheObj);
}
} }
__cache_unlock(pCacheObj);
} }
// else { // else {