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

[Andrea Arcangeli]

On Mon, May 10, 2010 at 12:41:07PM -0500, Christoph Lameter wrote:
> A simple way to disallow migration of pages is to increment the refcount
> of a page.

Ok for migrate but it won't prevent to crash in split_huge_page rmap
walk, nor the PG_lock. Why for a rmap bug have a migrate specific fix?
The fix that makes execve the only special place to handle in every
rmap walk, is at least more maintainable than a fix that makes one of
the rmap walk users special and won't fix the others, as there will be
more than just 1 user that requires this. My fix didn't make execve
special and it didn't require execve knowledge into the every rmap
walk like migrate (split_huge_page etc...) but as long as the kernel
doesn't crash I'm fine ;).
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