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Date:   Mon, 22 Feb 2021 18:27:18 +0000
From:   Matthew Garrett <mjg59@srcf.ucam.org>
To:     Mike Rapoport <rppt@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@kernel.org>,
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        David Hildenbrand <david@redhat.com>,
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        Matthew Wilcox <willy@infradead.org>,
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        Mike Rapoport <rppt@linux.ibm.com>,
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Subject: Re: [PATCH v17 08/10] PM: hibernate: disable when there are active
 secretmem users
Message-ID: <20210222182718.GA15105@codon.org.uk>
References: <20210208084920.2884-1-rppt@kernel.org>
 <20210208084920.2884-9-rppt@kernel.org>
 <20210222073452.GA30403@codon.org.uk>
 <20210222102359.GE1447004@kernel.org>
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On Mon, Feb 22, 2021 at 12:23:59PM +0200, Mike Rapoport wrote:
> On Mon, Feb 22, 2021 at 07:34:52AM +0000, Matthew Garrett wrote:
> > On Mon, Feb 08, 2021 at 10:49:18AM +0200, Mike Rapoport wrote:
> > 
> > > It is unsafe to allow saving of secretmem areas to the hibernation
> > > snapshot as they would be visible after the resume and this essentially
> > > will defeat the purpose of secret memory mappings.
> > 
> > Sorry for being a bit late to this - from the point of view of running
> > processes (and even the kernel once resume is complete), hibernation is
> > effectively equivalent to suspend to RAM. Why do they need to be handled
> > differently here?
> 
> Hibernation leaves a copy of the data on the disk which we want to prevent.

Who are you worried about seeing it, and at what points in time?