Red Hat Bugzilla – Bug 173895
Kernel panic on install on 64BG EM64T
Last modified: 2007-11-30 17:07:21 EST
Using RHEL4 U2's installer, a 64GB EM64T machine would panic on bootup with: Kernel panic - not syncing: map_single: bounce buffer is not DMA'ble " The problem is because of mem_map using up most of the low memory (because of 64GB physical memory) and kernel is not able to allocate swiotlb buffer in low memory. We have verified that things work fine by moving the swiotlb init earlier. " Patch from venkatesh.pallipadi@intel.com attached.
Created attachment 121337 [details] swiotlb_init_07.patch
This patch will work but another/better solution is to move the mem_map above the 4GB boundary. There is no reason that it needs to be at such a low address. I'll work with Intel on creating a patch that does this. Larry Woodman
This issue is on Red Hat Engineering's list of planned work items for the upcoming Red Hat Enterprise Linux 4.4 release. Engineering resources have been assigned and barring unforeseen circumstances, Red Hat intends to include this item in the 4.4 release.
Created attachment 127908 [details] x86_64_bootmem_alloc_fix.patch
Created attachment 127909 [details] x86_64_bootmem_alloc_fix.patch
Created attachment 127910 [details] x86_64_bootmem_alloc_fix.patch
Created attachment 127914 [details] x86_64_move_memmap_alloc_end.patch
Updated patches attached.
committed in stream U4 build 34.25. A test kernel with this patch is available from http://people.redhat.com/~jbaron/rhel4/
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 the 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-2006-0575.html