The upgrade is completed but there were errors during the upgrade process.

搜索升级输出,我发现了这个：

Setting up tar (1.22-2) ...

tar: ./md5sums: Cannot utime: Bad file descriptor
tar: ./control: Cannot utime: Bad file descriptor
tar: .: Cannot utime: Bad file descriptor
tar: Exiting with failure status due to prevIoUs errors
dpkg-deb: subprocess tar returned error exit status 2
dpkg: error processing /var/cache/apt/archives/diff_1%3a2.8.1-18_all.deb (--unpack):
 subprocess dpkg-deb --control returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/diff_1%3a2.8.1-18_all.deb
Exception during pm.DoInstall():  E:Sub-process /usr/bin/dpkg returned an error code (1)

Could not install the upgrades

The upgrade is now aborted. Your system could be in an unusable
state. A recovery will run now (dpkg --configure -a).

实际上,这是一个known bug.更多细节是here和here.

我将发布我找到的解决方法作为答案.