portage 坏掉了？[已解决]

$ sudo emerge --sync
Traceback (most recent call last):
 File "/usr/bin/emerge", line 29, in <module>
 import _emerge
 File "//usr/lib64/portage/pym/_emerge/__init__.py", line 25, in <module>
 import portage
ValueError: bad marshal data

$ tar jxf /usr/portage/distfiles/portage-*tar.bz2
$ cp -R pym bin /usr/lib/portage/