fix: deep copy ovfl cells to avoid double free

source/libs/tdb/src/db/tdbBtree.c

@@ -489,7 +489,7 @@ static int tdbBtreeBalanceDeeper(SBTree *pBt, SPage *pRoot, SPage **ppChild, TXN
   }
 
   // Copy the root page content to the child page
-  tdbPageCopy(pRoot, pChild);
+  tdbPageCopy(pRoot, pChild, 0);
 
   // Reinitialize the root page
   zArg.flags = TDB_BTREE_ROOT;
@@ -742,7 +742,7 @@ static int tdbBtreeBalanceNonRoot(SBTree *pBt, SPage *pParent, int idx, TXN *pTx
     for (int i = 0; i < nOlds; i++) {
       tdbPageCreate(pOlds[0]->pageSize, &pOldsCopy[i], tdbDefaultMalloc, NULL);
       tdbBtreeInitPage(pOldsCopy[i], &iarg, 0);
-      tdbPageCopy(pOlds[i], pOldsCopy[i]);
+      tdbPageCopy(pOlds[i], pOldsCopy[i], 0);
     }
     iNew = 0;
     nNewCells = 0;
@@ -840,7 +840,7 @@ static int tdbBtreeBalanceNonRoot(SBTree *pBt, SPage *pParent, int idx, TXN *pTx
     i8 flags = TDB_BTREE_ROOT | TDB_BTREE_PAGE_IS_LEAF(pNews[0]);
     // copy content to the parent page
     tdbBtreeInitPage(pParent, &(SBtreeInitPageArg){.flags = flags, .pBt = pBt}, 0);
-    tdbPageCopy(pNews[0], pParent);
+    tdbPageCopy(pNews[0], pParent, 1);
   }
 
   for (int i = 0; i < 3; i++) {

source/libs/tdb/src/db/tdbPage.c

@@ -229,7 +229,7 @@ int tdbPageDropCell(SPage *pPage, int idx, TXN *pTxn, SBTree *pBt) {
   return 0;
 }
 
-void tdbPageCopy(SPage *pFromPage, SPage *pToPage) {
+void tdbPageCopy(SPage *pFromPage, SPage *pToPage, int deepCopyOvfl) {
   int delta, nFree;
 
   pToPage->pFreeStart = pToPage->pPageHdr + (pFromPage->pFreeStart - pFromPage->pPageHdr);
@@ -250,8 +250,15 @@ void tdbPageCopy(SPage *pFromPage, SPage *pToPage) {
 
   // Copy the overflow cells
   for (int iOvfl = 0; iOvfl < pFromPage->nOverflow; iOvfl++) {
+    SCell *pNewCell = pFromPage->apOvfl[iOvfl];
+    if (deepCopyOvfl) {
+      int szCell = (*pFromPage->xCellSize)(pFromPage, pFromPage->apOvfl[iOvfl], 0, NULL, NULL);
+      pNewCell = (SCell *)tdbOsMalloc(szCell);
+      memcpy(pNewCell, pFromPage->apOvfl[iOvfl], szCell);
+    }
+
+    pToPage->apOvfl[iOvfl] = pNewCell;
     pToPage->aiOvfl[iOvfl] = pFromPage->aiOvfl[iOvfl];
-    pToPage->apOvfl[iOvfl] = pFromPage->apOvfl[iOvfl];
   }
   pToPage->nOverflow = pFromPage->nOverflow;
 }

source/libs/tdb/src/inc/tdbInt.h

@@ -333,7 +333,7 @@ void tdbPageInit(SPage *pPage, u8 szAmHdr, int (*xCellSize)(const SPage *, SCell
 int  tdbPageInsertCell(SPage *pPage, int idx, SCell *pCell, int szCell, u8 asOvfl);
 int  tdbPageDropCell(SPage *pPage, int idx, TXN *pTxn, SBTree *pBt);
 int  tdbPageUpdateCell(SPage *pPage, int idx, SCell *pCell, int szCell, TXN *pTxn, SBTree *pBt);
-void tdbPageCopy(SPage *pFromPage, SPage *pToPage);
+void tdbPageCopy(SPage *pFromPage, SPage *pToPage, int copyOvflCells);
 int  tdbPageCapacity(int pageSize, int amHdrSize);
 
 static inline SCell *tdbPageGetCell(SPage *pPage, int idx) {