2.6.15 failure on power4 iSeries

[Michael Ellerman]

On Tue, 24 Jan 2006 16:18, will schmidt wrote:
> > On my box at least, we're trying to allocate 0 bytes in
> > finish_device_tree(). lmb_alloc() happily does that, and reserves the 0
> > bytes for us. On my machine that reserved region gets coallesced with
> > another and so there's no bug, but perhaps on yours it doesn't get
> > coallesced and eventually it blows up in reserve_bootmem().
> >
> > Prior to benh's n_addrs patch finish_device_tree() wants to allocate 24
> > bytes, whereas with it it allocates 0 (for iSeries). So that's exposed
> > the bug in the lmb code.
>
> I narrowed down the bad lmb entry with size 0 to the finish_device_tree
> code,. so my test tree now contains this..
>
> #ifdef CONFIG_PPC_ISERIES
>          end = start = 0;
> #else
>          end = start = (unsigned long) __va(lmb_alloc(size, 128));
> #endif
>
> and I boot the rest of the way up.     Am not sure what the real fix should
> be, pretty sure this isnt it. :-)

Cool - we both tracked it to the same piece of code, which is always nice :)

I've got a patch that seems to do the trick, I'll post it in a sec.

cheers

-- 
Michael Ellerman
IBM OzLabs

email: michael:ellerman.id.au
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wwweb: http://michael.ellerman.id.au
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We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person
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