From 04ba45bd29341e04b40fe43e2c92a7bf2a311638 Mon Sep 17 00:00:00 2001
From: garenchan <garenchan23@gmail.com>
Date: Tue, 2 Nov 2021 11:44:05 +0800
Subject: [PATCH] Fix memory leak when host_cache_size is 0.

---
 sql/hostname.cc | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sql/hostname.cc b/sql/hostname.cc
index b6cf38d4c3ff..e74a988e29fe 100644
--- a/sql/hostname.cc
+++ b/sql/hostname.cc
@@ -199,6 +199,9 @@ static void add_hostname_impl(const char *ip_key, const char *hostname,
 
   if (likely(entry == NULL))
   {
+    if (!hostname_cache->size())
+      return;
+
     entry= (Host_entry *) malloc(sizeof (Host_entry));
     if (entry == NULL)
       return;
@@ -264,8 +267,10 @@ static void add_hostname_impl(const char *ip_key, const char *hostname,
 
   entry->m_errors.aggregate(errors);
 
-  if (need_add)
-    hostname_cache->add(entry);
+  if (need_add && hostname_cache->add(entry))
+  {
+    free(entry);
+  }
 
   return;
 }