From 3c684f1e694281a48c257496f09ccc61dde960fc Mon Sep 17 00:00:00 2001
From: Oleg Smirnov <olernov@gmail.com>
Date: Mon, 15 Jun 2026 13:28:20 +1000
Subject: [PATCH] MDEV-36344: UBSAN Lifo_buffer::have_space_for change

Adjust Lifo_buffer::have_space_for to not lead itself to UBSAN
overflows.
---
 sql/sql_lifo_buffer.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sql/sql_lifo_buffer.h b/sql/sql_lifo_buffer.h
index afe47b5f415..099e22055ed 100644
--- a/sql/sql_lifo_buffer.h
+++ b/sql/sql_lifo_buffer.h
@@ -174,7 +174,7 @@ public:
   uchar *end_of_space() override { return pos; }
   bool have_space_for(size_t bytes) override
   {
-    return (pos + bytes < end);
+    return (size_t) (end - pos) > bytes;
   }
 
   void write() override