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From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Alexander Potapenko <glider@google.com>
Cc:     Johannes Stezenbach <js@sig21.net>, Pavel Machek <pavel@ucw.cz>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Michal Hocko <mhocko@suse.cz>, linux-pm@vger.kernel.org
Subject: Re: init_on_free breaks hibernate
Date:   Tue, 14 Jan 2020 23:36:01 +0100
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On Tuesday, January 14, 2020 12:38:53 PM CET Alexander Potapenko wrote:
> > > Strange about the resume=/dev/vda, it worked for me the way I described it.
> > > Maybe device numbers are dynamic, 254:0 is what I got from ls -l /dev/vda.
> > Indeed, for me it's 253:0, and resuming from console works with that number.
> >
> > > > The memory corruption is also reproducible for me, taking a look.
> > >
> 
> I think I know what is causing the problem.
> Upon resume the free pages may contain stale information from the
> kernel that initiated the resume.
> There's clear_free_pages()
> (https://elixir.bootlin.com/linux/latest/source/kernel/power/snapshot.c#L1148)
> that clears the pages in the case CONFIG_PAGE_POISONING_ZERO is
> enabled, we just need to reuse it for init_on_free.
> See the potential fix below.
> 
> Rafael, Pavel, I've noticed that in the setup suggested by Johannes
> even the defconfig kernel with heap initialization cannot hibernate
> more than twice, the third hibernate hangs.
> Is that a known problem?

No, it is not.