From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Andres Lagar-Cavilla" <andres@lagarcavilla.org>
Subject: Re: [PATCH] x86/PoD: fix (un)locking after
 24772:28edc2b31a9b
Date: Mon, 13 Aug 2012 08:22:22 -0700
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To: Jan Beulich <JBeulich@suse.com>
Cc: George Dunlap <george.dunlap@eu.citrix.com>, Tim Deegan <tim@xen.org>, Andres Lagar-Cavilla <andres@lagarcavilla.org>, xen-devel <xen-devel@lists.xen.org>
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>>>> On 13.08.12 at 14:11, "Jan Beulich" <JBeulich@suse.com> wrote:
>> That c/s introduced a double unlock on the out-of-memory error path of
>> p2m_pod_demand_populate().
>
> I also wonder how correct that changeset's elimination of the page
> alloc lock in a number of places here is - p2m_pod_set_mem_target()'s
> calculations, for example, involve d->tot_pages, which with that lock
> not held can change under its feet.

afaict, access to d->tot_pages was not protected by the page_alloc lock
even prior to 24772.

Back when, I thought those unprotected tot_pages accesses should either be
locked or atomic_read(). Slipped through the cracks.

Andres

>
> Jan
>
>