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From: Henry Burns <henrywolfeburns@gmail.com>
To: "Agustín DallʼAlba" <agustin@dallalba.com.ar>
Cc: Vitaly Wool <vitalywool@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	 Seth Jennings <sjenning@redhat.com>,
	Dan Streetman <ddstreet@ieee.org>, Linux-MM <linux-mm@kvack.org>
Subject: Re: CRASH: General protection fault in z3fold
Date: Mon, 9 Sep 2019 21:08:14 -0400	[thread overview]
Message-ID: <CADJK47MDwK4zxRiO0W-K4ZCbcJ=pkUpyn3A9VvYD2GhgFybwtA@mail.gmail.com> (raw)
In-Reply-To: <28453b3deba00d9343fdcbde5bcda00e7615d321.camel@dallalba.com.ar>

On Mon, Sep 9, 2019 at 6:59 PM Agustín DallʼAlba
<agustin@dallalba.com.ar> wrote:
>
> On Mon, 2019-09-09 at 14:44 +0200, Vitaly Wool wrote:
> > On Mon, Sep 9, 2019 at 9:17 AM Vitaly Wool <vitalywool@gmail.com> wrote:
> > > On Mon, Sep 9, 2019 at 2:14 AM Agustín DallʼAlba <agustin@dallalba.com.ar> wrote:
> > > > However trace 2 (__zswap_pool_release blocked for more than xxxx
> > > > seconds) still happens.
> > >
> > > That one is pretty new and seems to have been caused by
> > > d776aaa9895eb6eb770908e899cb7f5bd5025b3c ("mm/z3fold.c: fix race
> > > between migration and destruction").
> > > I'm looking into this now and CC'ing Henry just in case.
> >
> > Agustin, could you please try reverting that commit? I don't think
> > it's working as it should.
> >
> > > ~Vitaly
>
> I reverted the commit and I haven't seen the deadlock happen again.
> Should I be experiencing some side effect of having reverted that?
>
> Thanks,
> Agustín
>
Hi Agustin,

Having reverted the commit you should only experience problems if you
are changing the zswap backend at runtime. There was a race condition
where a migrating page could avoid destruction and eventually crash
the kernel.

Best,
Henry


      reply	other threads:[~2019-09-10  1:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05  4:05 CRASH: General protection fault in z3fold Agustín DallʼAlba
2019-09-05 11:55 ` Vlastimil Babka
2019-09-08 11:09   ` Vitaly Wool
2019-09-09  0:14     ` Agustín DallʼAlba
2019-09-09  7:17       ` Vitaly Wool
2019-09-09 12:44         ` Vitaly Wool
2019-09-09 17:51           ` Henry Burns
2019-09-09 22:59           ` Agustín DallʼAlba
2019-09-10  1:08             ` Henry Burns [this message]

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