[Yum] Persistent YUM error, Fedora Core 2

[Matthew Watkins]

Hi Folks,

I've been having persistent problems with YUM package updates on one of 
our servers. It's not been retrieving updates for several weeks, and I 
become concerned about the security implications. I have found the 
solution to the problem this morning.

Basically, YUM would crash immediately after invocation, regardless of 
the arguments supplied:

[root at perky matt]# yum update
Traceback (most recent call last):
   File "/usr/share/yum/yummain.py", line 23, in ?
     import yum
   File "/usr/lib/python2.3/site-packages/yum/__init__.py", line 26, in ?
     import depsolve
   File "/usr/lib/python2.3/site-packages/yum/depsolve.py", line 29, in ?
     from repomd.packageSack import ListPackageSack
   File "/usr/lib/python2.3/site-packages/repomd/packageSack.py", line 
17, in ?
     import libxml2
   File "/usr/lib/python2.3/site-packages/libxml2.py", line 1, in ?
     import libxml2mod
ImportError: /usr/lib/python2.3/site-packages/libxml2mod.so: undefined 
symbol: xmlByteConsumed

I do some digging on Google and find other users with the same error, 
but no solution. I post to the Fedora-users list, but do not receive a 
reply. Having not had time to investigate for a while, I return to the 
problem this morning.  I find the following post through Google:

http://www.fedoraforum.org/forum/archive/index.php/t-21359.html

The final entry in the thread suggests checking for duplicate libxml2 
libraries. Seems like good advice:

[root at perky src]# locate libxml2.so
/usr/lib/libxml2.so
/usr/lib/libxml2.so.2
/usr/lib/libxml2.so.2.6.8
/usr/local/opt/brightmail/lib/libxml2.so
/usr/local/opt/brightmail/lib/libxml2.so.2

It looks like Brightmail Anti-spam has installed it's own copy of 
libxml2, which is probably why things have stopped working. This may 
seem like a trivial problem, but this will be difficult for some users 
to find and fix. An entry in the FAQ could potentially save users a lot 
of digging in search of this relatively simple solution!

Regards,

- Matt