Bug #46003 and bug #46034: backported the fixes from azalea.

sql/sql_base.cc

@@ -5095,7 +5095,13 @@ int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
     /* make * substituting permanent */
     SELECT_LEX *select_lex= thd->lex->current_select;
     select_lex->with_wild= 0;
-    select_lex->item_list= fields;
+    /*   
+      The assignment below is translated to memcpy() call (at least on some
+      platforms). memcpy() expects that source and destination areas do not
+      overlap. That problem was detected by valgrind. 
+    */
+    if (&select_lex->item_list != &fields)
+      select_lex->item_list= fields;
 
     thd->restore_active_arena(arena, &backup);
   }

sql/sql_select.cc

@@ -1748,7 +1748,8 @@ JOIN::exec()
       curr_join->having= curr_join->tmp_having= 0; // Allready done
     
     /* Change sum_fields reference to calculated fields in tmp_table */
-    curr_join->all_fields= *curr_all_fields;
+    if (curr_join != this)
+      curr_join->all_fields= *curr_all_fields;
     if (!items1)
     {
       items1= items0 + all_fields.elements;
@@ -1767,8 +1768,11 @@ JOIN::exec()
 				      fields_list.elements, all_fields))
 	  DBUG_VOID_RETURN;
       }
-      curr_join->tmp_all_fields1= tmp_all_fields1;
-      curr_join->tmp_fields_list1= tmp_fields_list1;
+      if (curr_join != this)
+      {
+        curr_join->tmp_all_fields1= tmp_all_fields1;
+        curr_join->tmp_fields_list1= tmp_fields_list1;
+      }
       curr_join->items1= items1;
     }
     curr_all_fields= &tmp_all_fields1;
@@ -1913,8 +1917,11 @@ JOIN::exec()
 				     tmp_fields_list2, tmp_all_fields2, 
 				     fields_list.elements, tmp_all_fields1))
 	  DBUG_VOID_RETURN;
-	curr_join->tmp_fields_list2= tmp_fields_list2;
-	curr_join->tmp_all_fields2= tmp_all_fields2;
+        if (curr_join != this)
+        {
+          curr_join->tmp_fields_list2= tmp_fields_list2;
+          curr_join->tmp_all_fields2= tmp_all_fields2;
+        }
       }
       curr_fields_list= &curr_join->tmp_fields_list2;
       curr_all_fields= &curr_join->tmp_all_fields2;
@@ -1969,8 +1976,11 @@ JOIN::exec()
       tmp_table_param.save_copy_field= curr_join->tmp_table_param.copy_field;
       tmp_table_param.save_copy_field_end=
 	curr_join->tmp_table_param.copy_field_end;
-      curr_join->tmp_all_fields3= tmp_all_fields3;
-      curr_join->tmp_fields_list3= tmp_fields_list3;
+      if (curr_join != this)
+      {
+        curr_join->tmp_all_fields3= tmp_all_fields3;
+        curr_join->tmp_fields_list3= tmp_fields_list3;
+      }
     }
     else
     {

sql/sql_select.h

@@ -416,7 +416,8 @@ class JOIN :public Sql_alloc
     group_optimized_away= 0;
 
     all_fields= fields_arg;
-    fields_list= fields_arg;
+    if (&fields_list != &fields_arg)      /* Avoid valgrind-warning */
+      fields_list= fields_arg;
     bzero((char*) &keyuse,sizeof(keyuse));
     tmp_table_param.init();
     tmp_table_param.end_write_records= HA_POS_ERROR;