Fix race condition in binlog dump thread during server shutdown.

There was missing a check for THD::killed after THD::enter_cond(). This could
cause the binlog dump thread to miss the kill signal during server shutdown
and hang until it was force-closed.

Also fix a race in a test case that occasionally fails in Buildbot.

mysql-test/include/rpl_init.inc

@@ -177,8 +177,8 @@ while ($_rpl_server)
   if (!$rpl_skip_reset_master_and_slave)
   {
     RESET MASTER;
-    RESET SLAVE;
     SET GLOBAL gtid_pos= "";
+    RESET SLAVE;
   }
   eval SET auto_increment_increment= $rpl_server_count;
   eval SET auto_increment_offset= $_rpl_server;

mysql-test/suite/rpl/r/rpl_gtid_basic.result

@@ -107,6 +107,7 @@ a	b
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = MASTER_MYPORT;
 include/start_slave.inc
+include/wait_for_slave_to_start.inc
 include/stop_slave.inc
 CHANGE MASTER TO master_host = '127.0.0.1', master_port = SLAVE_MYPORT;
 include/start_slave.inc

mysql-test/suite/rpl/t/rpl_gtid_basic.test

@@ -95,12 +95,16 @@ SELECT * FROM t2 ORDER BY a;
 --echo *** Now change everything back to what it was, to make rpl_end.inc happy
 # Also check that MASTER_USE_GTID=1 is still enabled.
 connection server_2;
+# We need to sync up server_2 before switching. If it happened to have reached
+# the point 'UPDATE t2 SET b="j1a" WHERE a=5' it will fail to connect to
+# server_1, which is (deliberately) missing that transaction.
+--let $wait_condition= SELECT COUNT(*) = 7 FROM t2
+--source include/wait_condition.inc
 --source include/stop_slave.inc
 --replace_result $MASTER_MYPORT MASTER_MYPORT
 eval CHANGE MASTER TO master_host = '127.0.0.1', master_port = $MASTER_MYPORT;
 --source include/start_slave.inc
---let $wait_condition= SELECT COUNT(*) = 7 FROM t2
---source include/wait_condition.inc
+--source include/wait_for_slave_to_start.inc
 
 connection server_3;
 --source include/stop_slave.inc

sql/sql_repl.cc

@@ -2263,6 +2263,8 @@ impossible position";
             thd->enter_cond(log_cond, log_lock,
                             "Master has sent all binlog to slave; "
                             "waiting for binlog to be updated");
+            if (thd->killed)
+              break;
             ret= mysql_bin_log.wait_for_update_bin_log(thd, heartbeat_ts);
             DBUG_ASSERT(ret == 0 || (heartbeat_period != 0));
             if (ret == ETIMEDOUT || ret == ETIME)
@@ -2294,7 +2296,7 @@ impossible position";
             {
               DBUG_PRINT("wait",("binary log received update or a broadcast signal caught"));
             }
-          } while (signal_cnt == mysql_bin_log.signal_cnt && !thd->killed);
+          } while (signal_cnt == mysql_bin_log.signal_cnt);
           thd->exit_cond(old_msg);
         }
         break;