This bug has been copied from bug #571544 and has been proposed to be backported to 5.5 z-stream (EUS).
in 2.6.18-194.4.1.el5
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: Hot-adding memory to a system with 4 GB of RAM caused problems with 32-bit DMA devices, which led to the system becoming unresponsive. With this update, the user is warned that more than 4 GB of RAM is being added to the system; however, memory exceeding 4 GB is not registered by the system. (BZ#587957)
Technical note updated. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. Diffed Contents: @@ -1 +1 @@ -Hot-adding memory to a system with 4 GB of RAM caused problems with 32-bit DMA devices, which led to the system becoming unresponsive. With this update, the user is warned that more than 4 GB of RAM is being added to the system; however, memory exceeding 4 GB is not registered by the system. (BZ#587957)+Hot-adding memory to a system with 4 GB of RAM caused problems with 32-bit DMA devices, which led to the system becoming unresponsive. With this update, the user is warned that more than 4 GB of RAM is being added to the system; however, memory exceeding 4 GB is not registered by the system.
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/RHSA-2010-0504.html