Messages in this thread | | | Date | Thu, 16 Dec 2010 14:58:14 -0800 | From | Yinghai Lu <> | Subject | Re: kdump broken on 2.6.37-rc4 |
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On 12/16/2010 02:01 PM, Vivek Goyal wrote: > On Thu, Dec 16, 2010 at 09:28:49AM -0800, Yinghai Lu wrote: >> On 12/16/2010 08:28 AM, H. Peter Anvin wrote: >>> On 12/16/2010 06:39 AM, Vivek Goyal wrote: >>>> On Wed, Dec 15, 2010 at 08:29:01PM -0800, Yinghai Lu wrote: >>>>> please check >>>>> >>>>> [PATCH] x86, crashkernel, 32bit: only try to get range under 512M >>>>> >>>>> Steanishlaw report kdump is 32bit is broken. >>>>> >>>>> in misc.c for decompresser, it will do sanity checking to make sure heap >>>>> heap under 512M. >>>> >>>> Thanks Yinghai. I am wondering why on 32bit heap has to be with-in 512MB. >>>> I think you are referring to following check in >>>> arch/x86/boot/compressed/misc.c. >>>> >>>> if (end > ((-__PAGE_OFFSET-(512 <<20)-1) & 0x7fffffff)) >>>> error("Destination address too large"); >>>> >>>> It was introduced here. >>>> >>>> commit 968de4f02621db35b8ae5239c8cfc6664fb872d8 >>>> Author: Eric W. Biederman <ebiederm@xmission.com> >>>> Date: Thu Dec 7 02:14:04 2006 +0100 >>>> >>>> [PATCH] i386: Relocatable kernel support >>>> >>>> Eric, >>>> >>>> It has been long. By any chance would you remember where does above >>>> constraint come from? >>>> >>> >>> It might, in fact, be bogus; specifically a proxy for the fact that we >>> need the kernel memory including bss and brk below the lowmem boundary, >>> which isn't well-defined. >> >> the brk is complaining if i change that to >> >> if (end > ((-__PAGE_OFFSET-(128 <<20)-1) & 0x7fffffff)) >> error("Destination address too large"); >> > > Yinghai, > > On my system above change works fine and I can boot into second kernel. So > it will boil down to knowing what are the exact constraints on heap for > decompression and for 32bit can we allow heap upto 896MB or not.
really? what is you CONFIG_PAGE_OFFSET? 0x40000000 or 0xc0000000?
Yinghai
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