Received-SPF: pass (google.com: domain of linux-kernel+bounces-174459-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <CABXGCsPktcHQOvKTbPaTwegMExije=Gpgci5NW=hqORo-s7diA@mail.gmail.com>
 <CABXGCsOC2Ji7y5Qfsa33QXQ37T3vzdNPsivGoMHcVnCGFi5vKg@mail.gmail.com> <0672f0b7-36f5-4322-80e6-2da0f24c101b@redhat.com>
In-Reply-To: <0672f0b7-36f5-4322-80e6-2da0f24c101b@redhat.com>
From: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Date: Thu, 9 May 2024 16:59:30 +0500
Message-ID: <CABXGCsN7LBynNk_XzaFm2eVkryVQ26BSzFkrxC2Zb5GEwTvc1g@mail.gmail.com>
Subject: Re: 6.9/BUG: Bad page state in process kswapd0 pfn:d6e840
To: David Hildenbrand <david@redhat.com>
Cc: Linux List Kernel Mailing <linux-kernel@vger.kernel.org>, 
	Linux Memory Management List <linux-mm@kvack.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Wed, May 8, 2024 at 10:45=E2=80=AFPM David Hildenbrand <david@redhat.com=
> wrote:
>
> "page dumped because: non-NULL mapping"
>
> Is the relevant bit. We are freeing a page, but page->mapping is not
> NULL. IIUC, it might happen under memory pressure when reclaiming memory.
>
> It's weird that only you are seeing that, if it would be something
> "obvious" I would expect multiple reports :/
>

Maybe because the problem is really difficult to reproduce (rare
combination of the kernel build option and workload). I even thought
that the problem was fixed because it did not reproduce itself for a
week.

But yesterday when it happened again with the kworker process, I
stopped doubting that it was fixed.

Now I am concerned with the question of how to be as useful as
possible when reproducing bug again?

--=20
Best Regards,
Mike Gavrilov.