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Date:   Mon, 17 Oct 2022 15:24:23 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Oleksandr Natalenko <oleksandr@natalenko.name>
Cc:     Brian Foster <bfoster@redhat.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Seth Jennings <sjenning@redhat.com>,
        Dan Streetman <ddstreet@ieee.org>,
        Vitaly Wool <vitaly.wool@konsulko.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Matthew Wilcox <willy@infradead.org>
Subject: Re: Panic/lockup in z3fold_zpool_free
Message-Id: <20221017152423.37a126325b4330e71cf8f869@linux-foundation.org>
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On Mon, 17 Oct 2022 18:34:50 +0200 Oleksandr Natalenko <oleksandr@natalenko.name> wrote:

> > > > I'll give it a try. The only problem is that for me the issue is not reproducible at will, it can take 1 day, or it can take 2 weeks before the panic is hit.
> > > > 
> > > > > [1] https://lore.kernel.org/linux-mm/YxDyZLfBdFHK1Y1P@bfoster/
> > > > > [2] https://lore.kernel.org/linux-mm/20220906190602.1626037-1-bfoster@redhat.com/
> > > 
> > > So far, I haven't reproduced this issue with your patch. I haven't run the machine sufficiently long, just under a week, so this is rather to let you know that I haven't abandoned testing.
> > > 
> > 
> > Thanks for the update. Is this still going well, or reached a point
> > where you typically see the problem? I can still reproduce the original
> > problem so I may have to ping the patch again..
> 
> So far, no issue observed with your patch.

Thanks.

It's actually unclear (to me) why Matthew's b653db77350c73 ("mm: Clear
page->private when splitting or migrating a page") was considered
necessary.  What problem did it solve?

https://lore.kernel.org/linux-mm/20220906190602.1626037-1-bfoster@redhat.com/
is a partial undoing of that change, but should we simply revert
b653db77350c73?