This bug has been copied from bug #637920 and has been proposed to be backported to 5.5 z-stream (EUS).
Built in 1.39-23.el5_5.1
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: Under certain circumstances, the blkid utility may have produced an empty output when the /etc/blkid/blkid.tab file contained multiple stale entries with the same label. Consequent to this, an attempt to check the file system or mount it may have failed, preventing the system from booting. This error has been fixed, and the underlying source code has been modified to ensure that blkid always returns the expected result.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2010-0868.html