From f3b6d56fb2eb8ff2b0c98336339ceeffdfc6c26e Mon Sep 17 00:00:00 2001
From: "davi@moksha.local" <>
Date: Sat, 29 Sep 2007 16:04:31 -0300
Subject: [PATCH] The fix for BUG 21136 (ChangeSet@1.2611.1.1) introduced a
 regression that caused a few tests to fail because the thd->extra_lock wasn't
 being set to NULL after the table was unlocked. This poses a serious problem
 because later attempts to access thd->extra_lock (now a dangling pointer)
 will probably result in a crash (undefined behavior) -- and that's what
 actually happens in some test cases.

The solution is to set the select_create::m_plock pointee to NULL, which
means that thd->extra_lock is set to NULL when the lock data is not for a
temporary table.
---
 sql/sql_insert.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
index fedda29c249..b4f2d8c65f2 100644
--- a/sql/sql_insert.cc
+++ b/sql/sql_insert.cc
@@ -3653,7 +3653,8 @@ bool select_create::send_eof()
     if (m_plock)
     {
       mysql_unlock_tables(thd, *m_plock);
-      m_plock= 0;
+      *m_plock= NULL;
+      m_plock= NULL;
     }
   }
   return tmp;
@@ -3691,7 +3692,8 @@ void select_create::abort()
   if (m_plock)
   {
     mysql_unlock_tables(thd, *m_plock);
-    m_plock= 0;
+    *m_plock= NULL;
+    m_plock= NULL;
   }
 
   if (table)