From d8d9f79e09dfe822586742a62928ce37c44aaa90 Mon Sep 17 00:00:00 2001
From: unknown <guilhem@mysql.com>
Date: Mon, 10 Jan 2005 13:52:32 +0100
Subject: [PATCH] Fix for BUG#7658 "optimize crashes slave thread (1 in
 1000)]": mysql_admin_table() attempted to write to a vio which was 0. I could
 have fixed mysql_admin_table() but fixing my_net_write() looked more
 future-proof.

sql/net_serv.cc:
  If no VIO, no write.
---
 sql/net_serv.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sql/net_serv.cc b/sql/net_serv.cc
index e5cb4d1e815..cad1f041005 100644
--- a/sql/net_serv.cc
+++ b/sql/net_serv.cc
@@ -227,6 +227,8 @@ int
 my_net_write(NET *net,const char *packet,ulong len)
 {
   uchar buff[NET_HEADER_SIZE];
+  if (unlikely(!net->vio)) // nowhere to write
+    return 0;
   /*
     Big packets are handled by splitting them in packets of MAX_PACKET_LENGTH
     length. The last packet is always a packet that is < MAX_PACKET_LENGTH.