Red Hat Bugzilla – Bug 446188
BUG: Don't reserve crashkernel memory > 4 GB on ia64
Last modified: 2010-03-14 17:31:54 EDT
Description of problem:
Some IA64 machines map all cell-local memory above 4 GB (32 bit limit).
However, in most cases, the kernel needs some memory below that limit that is
DMA-capable. So in this machine configuration, the crashkernel will be reserved
above 4 GB.
For machines that use SWIOTLB implementation because they lack an I/O MMU
the low memory is required by the SWIOTLB implementation. In that case,
it doesn't make sense to reserve the crashkernel at all because it's unusable
Version-Release number of selected component (if applicable): 2.6.18-92.el5
How reproducible: 100% on certain systems
Steps to Reproduce:
1. Boot with crashkernel > 4GB
Actual results: Varied -- some systems hang, others panic.
Expected results: No hangs or panics
Additional info: Upstream patch attached.
Created attachment 305230 [details]
Upstream fix for this issue
Doug, do you have an HP system that requires 'machvec=dig' on the kdump boot
line? ISTR an issue about adding 'machvec=dig' to the kdump boot line ...
Answered my own question ;)
Adding jwilson -- when a final patch is posted you'll have to test xen-ia64.
Hm... Only machine I've got that requires machvec=dig has only 4GB of memory,
not sure what sort of mapping its got... Can probably get a machine in RHTS to
work with though. Or do I correctly recall that you have an rx2620 that
(according to bug 218667) also needs machvec=dig?
Yeah -- I'm just about to start testing there.
/me is using a larger system to compile ATM.
Created attachment 305679 [details]
RHEL5 fix for this issue
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
You can download this test kernel from http://people.redhat.com/dzickus/el5
This bug has been marked for inclusion in the Red Hat Enterprise Linux 5.3
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this is not the same as 'the bug doesn't present anymore')
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
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