On 07/14/2012 03:58 AM, Dr Andrew C Aitchison wrote:
> On Fri, 13 Jul 2012, Pat Riehecky wrote:
>
>> There have been a number of questions regarding problem with starting 
>> X after the recent security update.  This email is an attempt to 
>> summarize the situation, provide insight, demonstrate the process as 
>> a whole, and clear up some confusion with the solution.
>
>> Cause:
>>
>> At the root of the problem was the security update for 
>> xorg-x11-server published on July 9th.  The problem was caused by a 
>> change in the module ABI for loading xorg drivers that happened in 
>> SL6.2.  That change was a bugfix and not a security update, so it was 
>> not pushed out to earlier releases.  The security update for 
>> xorg-x11-server uses the new ABI. The package, however, does not 
>> force the use of these newer drivers though any rpm dependency tools 
>> - such as requires, conflicts, or obsoletes. Thus the xorg-x11-drv 
>> update can be installed without incident, even though it will not 
>> work as expected.  Our usual dependency resolution process is unable 
>> to locate and report dependencies that are not listed by the 
>> package.  The change in the ABI happened with SL6.2, but none of the 
>> xorg packages were security errata at that time.  So, we didn't catch 
>> the problem then as we didn't have to integrate the 6.2 ABI with the 
>> 6.1 ABI.
>>
>>
>> On the period in testing:
>>
>> The xorg-x11-server package was in the sl-testing repository for 12 
>> days before the date of release.
>> I received a few reports from people who tested the packages while 
>> they were in testing.  It appears that those testers were on 6.2 and 
>> thus didn't run into the incompatibility problem.  There were no 
>> problems reported with this package during the testing window.
>
> In that case I may have a different problem.
> My two test machines which failed were running 6.2 with (to the best 
> of my knowledge) all updates. They may have been updated from earlier
> 6.1 releases, but both have had sl-release-6.2-1.1 at least since May.
>
> I guess that my problems are slightly different from others as
> I can't get a console or ssh connection to the broken machines,
> but others seem to be able to.
>
> I now regret not posting a "my machine wont boot with the 6.3
> security updates in testing for 6.2" without any useful information
> about what or why, but until I had time to boot from a Live-DVD
> I had no way of communicating with the machine.
>
> Sorry if I'm a bit short, but in spite of probably a day's
> work on this my laptop is still a brick.
>

Sorry to hear that.

Any chance for a copy of some relevant system logs?

Does booting the box without 'rhgb quiet' on the grub kernel args menu 
provide any insights as to what is keeping the box from booting?

Pat


-- 
Pat Riehecky
Scientific Linux Developer