From 20fbb3c3b967bb4e8325636c72f06aae1f121bcd Mon Sep 17 00:00:00 2001
From: Georg Richter <georg@mariadb.com>
Date: Mon, 29 Apr 2024 10:57:12 +0200
Subject: [PATCH] Avoid possible crash if connection was closed

Before checking pending result sets in prepared statements,
we need to check if the connection was already closed or
resetted by checking stmt->mysql. In case of NULL we return
false, since there are no more pending result sets.
---
 libmariadb/mariadb_stmt.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libmariadb/mariadb_stmt.c b/libmariadb/mariadb_stmt.c
index 4f99ab01..cbf88eed 100644
--- a/libmariadb/mariadb_stmt.c
+++ b/libmariadb/mariadb_stmt.c
@@ -127,7 +127,12 @@ void stmt_set_error(MYSQL_STMT *stmt,
    pending result set */
 static my_bool madb_have_pending_results(MYSQL_STMT *stmt)
 {
-  LIST *li_stmt= stmt->mysql->stmts;
+  LIST *li_stmt;
+
+  if (!stmt->mysql)
+    return 0;
+
+  li_stmt= stmt->mysql->stmts;
   for (;li_stmt;li_stmt= li_stmt->next)
   {
     MYSQL_STMT *s= (MYSQL_STMT *)li_stmt->data;