Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages()and rmap_walk() during migration by not migrating temporary stacks

[Mel Gorman]

On Sat, May 01, 2010 at 08:56:18PM -0500, Christoph Lameter wrote:
> On Thu, 29 Apr 2010, Mel Gorman wrote:
> 
> > There is a race between shift_arg_pages and migration that triggers this bug.
> > A temporary stack is setup during exec and later moved. If migration moves
> > a page in the temporary stack and the VMA is then removed before migration
> > completes, the migration PTE may not be found leading to a BUG when the
> > stack is faulted.
> 
> A simpler solution would be to not allow migration of the temporary stack?
> 

The patch's intention is to not migrate pages within the temporary
stack. What are you suggesting that is different?

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab
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