tsdb/read2: fix UAF

source/dnode/vnode/src/tsdb/tsdbMergeTree.c

@@ -426,7 +426,6 @@ int32_t tLDataIterOpen2(struct SLDataIter *pIter, SSttFileReader *pSttFileReader
       return code;
     }
 
-    // code = loadSttTombDataForAll(pReader1, pIter->pReader, pBlockLoadInfo);
     code = loadTombFn(pReader1, pIter->pReader, pBlockLoadInfo);
 
     double el = (taosGetTimestampUs() - st) / 1000.0;

source/dnode/vnode/src/tsdb/tsdbRead2.c

@@ -4928,9 +4928,10 @@ void tsdbUntakeReadSnap2(STsdbReader* pReader, STsdbReadSnap* pSnap, bool proact
     tsdbFSUnref(pTsdb, &pSnap->fs);
     if (pSnap->pNode) taosMemoryFree(pSnap->pNode);
     if (pSnap->pINode) taosMemoryFree(pSnap->pINode);
-    taosMemoryFree(pSnap);
 
     tsdbFSDestroyRefSnapshot(&pSnap->pfSetArray);
+
+    taosMemoryFree(pSnap);
   }
   tsdbTrace("vgId:%d, untake read snapshot", TD_VID(pTsdb->pVnode));
 }