Better handle a case of database corruption where a b-tree page is one of its own ancestor pages.

FossilOrigin-Name: a24e46804893a7e6e8f3130abca882f9a3aa3b7b2b82aa39a0a20856172766d5

1 files changed, 5 insertions, 0 deletions

diff --git a/src/btree.c b/src/btree.c
index a08ed95d1..6dc92a950 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -8774,6 +8774,11 @@ static int balance(BtCursor *pCur){
       }else{
         break;
       }
+    }else if( sqlite3PagerPageRefcount(pPage->pDbPage)>1 ){
+      /* The page being written is not a root page, and there is currently
+      ** more than one reference to it. This only happens if the page is one 
+      ** of its own ancestor pages. Corruption. */
+      rc = SQLITE_CORRUPT_BKPT;
     }else{
       MemPage * const pParent = pCur->apPage[iPage-1];
       int const iIdx = pCur->aiIdx[iPage-1];