In our upgrade from SL 6.3 to 6.5, we experience a change to hwloc library 
version, breaking binary applications.

My understanding was that I could expect ABI compatibility to be preserved 
in an upgrade between minor releases like this. Are we incorrect to make 
this assumption?

I found this document [1] from upstream which goes some way to documenting 
the upstream version 7, is there similar documentation for version 6 or 
SL6?

Many thanks

On SL 6.5:

  $ rpm -q hwloc
  hwloc-1.5-1.el6.x86_64

  $ ls -l /usr/lib64/libhwloc.so.5*
  lrwxrwxrwx 1 root root     17 Jul 27 23:58 /usr/lib64/libhwloc.so.5 -> libhwloc.so.5.1.0
  -rwxr-xr-x 1 root root 166336 Feb 22  2013 /usr/lib64/libhwloc.so.5.1.0

On SL 6.3:

  $ rpm -q hwloc
  hwloc-1.1-0.1.el6.x86_64

  $ ls -l /usr/lib64/libhwloc.so.1*
  lrwxrwxrwx 1 root root     17 Jun 25 06:38 /usr/lib64/libhwloc.so.1 -> libhwloc.so.1.0.1
  -rwxr-xr-x 1 root root 110392 May 20  2011 /usr/lib64/libhwloc.so.1.0.1

[1] https://access.redhat.com/articles/rhel-abi-compatibility

-- 
Mark