After an upgrading with yum program, yum will end with segmentation fault.
Last link about libz is the cause:
-rwxr-xr-x 1 root root 75028 9 gen 2007 libz.so.1.2.3
-rwxr-xr-x 1 root bin 96572 8 nov 2010 libz.so.1.2.5
-rw-r–r– 1 root bin 101462 8 nov 2010 libz.a
lrwxrwxrwx 1 root root 13 8 apr 2011 libz.so -> libz.so.1.2.3
lrwxrwxrwx 1 root root 13 8 apr 2011 libz.so.1 -> libz.so.1.2.5
libz.so.1 need a different link:
lrwxrwxrwx 1 root root 13 8 apr 2011 libz.so.1 -> libz.so.1.2.3
Reference: yum fails with segfault after source zlib upgrade