=== modified file 'ChangeLog'
--- ChangeLog	2013-07-30 13:40:01 +0000
+++ ChangeLog	2013-08-01 05:25:34 +0000
@@ -22,6 +22,8 @@
     (Bug# 16176981/67793)
   * Conversion of Time field data to Timestamp type may produce incorrect result
     (Bug# 17016839/69545)
+  * Need to add a lock to access connections member in ENV structure
+    (Bug# 17240611/69864)
 
 
 ----

=== modified file 'driver/driver.h'
--- driver/driver.h	2013-03-20 10:13:21 +0000
+++ driver/driver.h	2013-08-01 06:27:15 +0000
@@ -330,7 +330,9 @@
   SQLINTEGER   odbc_ver;
   LIST	       *connections;
   MYERROR      error;
-
+#ifdef THREAD
+  pthread_mutex_t lock;
+#endif
 } ENV;
 
 

=== modified file 'driver/handle.c'
--- driver/handle.c	2012-12-13 23:31:25 +0000
+++ driver/handle.c	2013-08-01 07:49:19 +0000
@@ -62,6 +62,7 @@
 
 SQLRETURN SQL_API my_SQLAllocEnv(SQLHENV FAR *phenv)
 {
+  ENV FAR **env= (ENV FAR**) phenv;
 #ifdef _UNIX_
   /* Init thread key just once for all threads */
   pthread_once(&myodbc_thread_key_inited, myodbc_thread_key_create);
@@ -85,7 +86,7 @@
         return SQL_ERROR;
     }
 #endif /* _UNIX_ */
-
+    pthread_mutex_init(&(*env)->lock,NULL);
     return SQL_SUCCESS;
 }
 
@@ -121,6 +122,7 @@
 
 SQLRETURN SQL_API my_SQLFreeEnv(SQLHENV henv)
 {
+    ENV FAR *env= (ENV FAR*) henv;
 #ifndef _UNIX_
     GlobalUnlock(GlobalHandle((HGLOBAL) henv));
     GlobalFree(GlobalHandle((HGLOBAL) henv));
@@ -128,6 +130,7 @@
     x_free(henv);
     myodbc_end();
 #endif /* _UNIX_ */
+    pthread_mutex_destroy(&env->lock);
     return(SQL_SUCCESS);
 }
 
@@ -245,7 +248,9 @@
     dbc->last_query_time= (time_t) time((time_t*) 0);
     dbc->txn_isolation= DEFAULT_TXN_ISOLATION;
     dbc->env= penv;
+    pthread_mutex_lock(&penv->lock);
     penv->connections= list_add(penv->connections,&dbc->list);
+    pthread_mutex_unlock(&penv->lock);
     dbc->list.data= dbc;
     dbc->unicode= 0;
     dbc->ansi_charset_info= dbc->cxn_charset_info= NULL;
@@ -283,7 +288,9 @@
     LIST *ldesc;
     LIST *next;
 
+    pthread_mutex_lock(&dbc->env->lock);
     dbc->env->connections= list_delete(dbc->env->connections,&dbc->list);
+    pthread_mutex_unlock(&dbc->env->lock);
     x_free(dbc->database);
     if (dbc->ds)
       ds_delete(dbc->ds);
@@ -682,7 +689,9 @@
   /* add to this connection's list of explicit descriptors */
   e= (LIST *) my_malloc(sizeof(LIST), MYF(0));
   e->data= desc;
+  pthread_mutex_lock(&dbc->lock);
   dbc->exp_desc= list_add(dbc->exp_desc, e);
+  pthread_mutex_unlock(&dbc->lock);
 
   *pdesc= desc;
   return SQL_SUCCESS;
@@ -712,7 +721,9 @@
   {
     if (ldesc->data == desc)
     {
+      pthread_mutex_lock(&dbc->lock);
       dbc->exp_desc= list_delete(dbc->exp_desc, ldesc);
+      pthread_mutex_unlock(&dbc->lock);
       x_free(ldesc);
       break;
     }

=== modified file 'driver/options.c'
--- driver/options.c	2013-06-28 16:53:41 +0000
+++ driver/options.c	2013-08-01 07:37:10 +0000
@@ -608,6 +608,7 @@
                 /* otherwise, associate this statement with the desc */
                 LIST *e= (LIST *) my_malloc(sizeof(LIST), MYF(0));
                 e->data= stmt;
+                /* No need to lock */
                 desc->exp.stmts= list_add(desc->exp.stmts, e);
               }