CVE request: xen: request-processing loop is unbounded in blkback

[Eugene Teo <eugene () redhat com>]

If the frontend pass a bad index of production request, the backend will 
enter an endless loop and then cause a excessive CPU consumption. A Xen 
guest can cause the Xen host to be unresponsive.

This issue has been fixed in upstream by:
changeset:   391:77f831cbb91d
user:        Keir Fraser <keir.fraser () citrix com>
date:        Fri Jan 18 16:52:25 2008 +0000
summary:     blkback: Request-processing loop is unbounded and hence 
requires a
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/77f831cbb91d

changeset:   392:7070d34f251c
user:        Keir Fraser <keir.fraser () citrix com>
date:        Mon Jan 21 11:43:31 2008 +0000
summary:     blkback/blktap: Check for kthread_should_stop() in inner loop,
http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/7070d34f251c

Thanks, Eugene