Merge pull request #4362 from taosdata/hotfix/TD-2184

fix TD-2184

src/tsdb/src/tsdbMemTable.c

@@ -871,10 +871,10 @@ static void tsdbFreeRows(STsdbRepo *pRepo, void **rows, int rowCounter) {
                 listNEles(pRepo->mem->bufBlockList), pBufBlock->offset, pBufBlock->remain);
 
       if (pBufBlock->offset == 0) {  // return the block to buffer pool
-        tsdbLockRepo(pRepo);
+        if (tsdbLockRepo(pRepo) < 0) return;
         SListNode *pNode = tdListPopTail(pRepo->mem->bufBlockList);
         tdListPrependNode(pBufPool->bufBlockList, pNode);
-        tsdbUnlockRepo(pRepo);
+        if (tsdbUnlockRepo(pRepo) < 0) return;
       }
     } else {
       ASSERT(listNEles(pRepo->mem->extraBuffList) > 0);

src/util/src/tskiplist.c

@@ -291,7 +291,10 @@ bool tSkipListIterNext(SSkipListIterator *iter) {
     iter->next = SL_NODE_GET_FORWARD_POINTER(iter->cur, 0);
     iter->step++;
   } else {
-    if (iter->cur == pSkipList->pHead) return false;
+    if (iter->cur == pSkipList->pHead) {
+      tSkipListUnlock(pSkipList);
+      return false;
+    }
     iter->cur = SL_NODE_GET_BACKWARD_POINTER(iter->cur, 0);
 
     // a new node is inserted into between iter->cur and iter->next, ignore it