[FZH] yum 的问题

[dhyang]

升级过一次yum之后，每次使用总出现如下信息，yum暂停，使用ctrl+c中断后，再
输入一次命令才能正常使用yum，何解？
错误信息如下：
[yang@fedora ~]$ su
密码：
[root@fedora yang]# yum check-update
已加载插件：aliases, auto-update-debuginfo, basearchonly, changelog,
downloadonly,
          : fastestmirror, filter-data, fs-snapshot, keys, list-data,
local,
          : merge-conf, post-transaction-actions, presto, priorities,
protect-
          : packages, protectbase, refresh-packagekit, refresh-updatesd,
remove-
          : with-leaves, rhnplugin, rpm-warm-cache, security,
show-leaves,
          : tmprepo, tsflags, upgrade-helper, verify, versionlock
This system is not registered with RHN.
RHN support will be disabled.

yum 版本信息如下：
[root@fedora yang]# yum --version
3.2.27
  Installed: rpm-4.7.2-1.fc12.i686 at 2010-03-20 17:14
  Built    : Fedora Project at 2009-12-08 12:05
  Committed: Panu Matilainen <pmatilai(a)redhat.com&gt; at 2009-12-08

  Installed: yum-3.2.27-2.fc12.noarch at 2010-03-28 04:17
  Built    : Fedora Project at 2010-03-23 14:39
  Committed: Seth Vidal <skvidal at fedoraproject.org> at 2010-03-23

  Installed: yum-plugin-aliases-1.1.26-1.fc12.noarch at 2010-03-22 15:56
  Built    : Fedora Project at 2010-02-10 06:07
  Committed: Tim Lauridsen <timlau(a)fedoraproject.org&gt; at 2010-02-10

  Installed: yum-plugin-fastestmirror-1.1.26-1.fc12.noarch at 2010-03-22
15:56
  Built    : Fedora Project at 2010-02-10 06:07
  Committed: Tim Lauridsen <timlau(a)fedoraproject.org&gt; at 2010-02-10