linux-kernel - Re: PS3: trouble with SPARSEMEM

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Date:	Wed, 05 Dec 2007 15:45:10 -0800
From:	Geoff Levand <geoffrey.levand@...sony.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>,
	miltonm@....com, clameter@....com, apw@...dowen.org,
	linux-kernel@...r.kernel.org, y-goto@...fujitsu.com
Subject: Re: PS3: trouble with SPARSEMEM_VMEMMAP and kexec

Andrew Morton wrote:
> On Wed, 5 Dec 2007 10:52:48 +0100 (CET)
> Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com> wrote:
> 
>> --------------------------------------------------------------------------------
>> Subject: sparsemem: sparse_add_one_section() may fail to allocate memory
>> 
>> sparsemem: sparse_add_one_section() may fail to allocate memory, and must check
>> whether the allocation succeeded before proceeding to touch the allocated
>> memory.
>> 
>> From: Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>
>> 
>> Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>
>> ---
>> FIXME There are still some possible memory leaks in sparse_add_one_section():
>>   - usemap is never deallocated
>>   - __kfree_section_memmap() is a not yet implemented dummy
> 
> I already had
> 
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.24-rc4/2.6.24-rc4-mm1/broken-out/mm-sparsec-improve-the-error-handling-for-sparse_add_one_section.patch
> and
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.24-rc4/2.6.24-rc4-mm1/broken-out/mm-sparsec-check-the-return-value-of-sparse_index_alloc.patch
> 
> queued.  Do they fix the problem, and should they be merged in 2.6.24?

No, a quick test shows it just panics in a different place.  Geert's
patch does also.

I'll try Milton's suggestion to pre-allocate the memory early.  It seems
that should work as long as nothing else before the hot-plug mem is added
needs a large chunk.

-Geoff

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