On 01/11/2013 02:39 AM, Dave Anderson wrote: > > > ----- Original Message ----- >> >> Our QA group recently ran into a makedumpfile problem while >> testing kdump/makedumpfile w/upstream 3.7.1 kernels, which >> had to do with the filtering of pages on a 12GB ppc64 system. >> > ... [ cut ] ... >> >> I haven't checked why the original math fails in the case of the >> ppc64 kernel, while it does not fail in a CONFIG_SPARSEMEM_EXTREME >> x86_64 kernel, for example. (page size maybe?) But obviously the >> simpler dimemsion-check is a better way to do it. >> >> Of course, within the current constraints of makedumpfile, it's not >> that easy. Ideally the kernel could pass the configuration in >> the vmcoreinfo with a VMCOREINFO_CONFIG(name). But anyway, I'll leave >> that up to you. >> >> Thanks, >> Dave > > It's presumably being seen in 3.7.1 because of this commit: > > $ git log -p arch/powerpc/include/asm/sparsemem.h > commit 048ee0993ec8360abb0b51bdf8f8721e9ed62ec4 > Author: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com> > Date: Mon Sep 10 02:52:55 2012 +0000 > > powerpc/mm: Add 64TB support > > Increase max addressable range to 64TB. This is not tested on > real hardware yet. > > Reviewed-by: Paul Mackerras <paulus at samba.org> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com> > Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org> > > diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h > index 0c5fa31..f6fc0ee 100644 > --- a/arch/powerpc/include/asm/sparsemem.h > +++ b/arch/powerpc/include/asm/sparsemem.h > @@ -10,8 +10,8 @@ > */ > #define SECTION_SIZE_BITS 24 > > -#define MAX_PHYSADDR_BITS 44 > -#define MAX_PHYSMEM_BITS 44 > +#define MAX_PHYSADDR_BITS 46 > +#define MAX_PHYSMEM_BITS 46 > > #endif /* CONFIG_SPARSEMEM */ > > $ git describe --contains 048ee0993ec8360abb0b51bdf8f8721e9ed62ec4 > v3.7-rc1~108^2~32 > $ > > Dave Similar issue was seen on s390x last year (http://lists.infradead.org/pipermail/kexec/2011-December/005905.html). The change in MAX_PHYSMEM_BITS define in kernel causes sparsemem extreme check to fail in makedumpfile. This needs to be fixed in the same way as it was on s390x. Will post a fix patch for makedumpfile after testing it on upstream kernel. Thanks, -Mahesh.
