A patch from Kristian:

Remove rpl_group_info from THD before freeing it,
to avoid access-after-free in THD.

sql/slave.cc

@@ -4568,6 +4568,7 @@ log '%s' at position %s, relay log '%s' position: %s%s", RPL_LOG_NAME,
   serial_rgi->thd= rli->sql_driver_thd= 0;
   mysql_mutex_lock(&LOCK_thread_count);
   THD_CHECK_SENTRY(thd);
+  thd->rgi_fake= thd->rgi_slave= NULL;
   delete serial_rgi;
   delete thd;
   mysql_mutex_unlock(&LOCK_thread_count);