Merge from 5.0

******
manual merge 5.0-bugteam --> 5.1-bugteam (bug 38816)

1 files changed, 3 insertions, 5 deletions

diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index a1f6798244e..35dbb64dfef 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -1768,16 +1768,14 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose)
 
         thd_info->start_time= tmp->start_time;
         thd_info->query=0;
+        /* Lock THD mutex that protects its data when looking at it. */
+        pthread_mutex_lock(&tmp->LOCK_thd_data);
         if (tmp->query)
         {
-	  /* 
-            query_length is always set to 0 when we set query = NULL; see
-	    the comment in sql_class.h why this prevents crashes in possible
-            races with query_length
-          */
           uint length= min(max_query_length, tmp->query_length);
           thd_info->query=(char*) thd->strmake(tmp->query,length);
         }
+        pthread_mutex_unlock(&tmp->LOCK_thd_data);
         thread_infos.append(thd_info);
       }
     }