[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH for-4.6] xen/mm: populate_physmap: validate correctly the gfn for direct mapped domain

>>> On 13.08.15 at 12:14, <ian.campbell@xxxxxxxxxx> wrote:
> There isn't a race here is there? What if the reference were dropped after
> this check but before the guest_physmap_add_page (which takes new
> references)? We are implicitly relying on a guarantee made elsewhere that a
> direct mapped guest never drops the final ref until it is destroyed (which
> can't be happening in this window I think), but it would be obviously safer
> against such bugs if we just held the ref until after the p2m was updated.

Yeah, we depend on this, and what you suggest would indeed be
an improvment.

> Another thing for a future/4.7 cleanup I guess.


But as bottom line I take it that your objections to the patch going in
soon have been eliminated?


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.