Re: [PATCH][RFC] fix kernel BUG at mm/migrate.c:719! in 2.6.26-rc5-mm3

[Hugh Dickins]

On Tue, 17 Jun 2008, Lee Schermerhorn wrote:
> 
> Now I wonder if the assertion that newpage count == 1 could be violated?
> I don't see how.  We've just allocated and filled it and haven't
> unlocked it yet, so we should hold the only reference.  Do you agree?

Disagree: IIRC, excellent example of the kind of assumption
that becomes invalid with Nick's speculative page references.

Someone interested in the previous use of the page may have
incremented the refcount, and in due course will find that
it's got reused for something else, and will then back off.

Hugh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/