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From: Matthew Wilcox <willy@infradead.org>
To: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: linux-fsdevel@vger.kernel.org,
	fuse-devel <fuse-devel@lists.sourceforge.net>,
	linux-mm <linux-mm@kvack.org>, miklos <mszeredi@redhat.com>,
	"André Almeida" <andrealmeid@collabora.com>
Subject: Re: [fuse-devel] fuse: trying to steal weird page
Date: Sun, 3 May 2020 13:06:15 -0700	[thread overview]
Message-ID: <20200503200615.GA16070@bombadil.infradead.org> (raw)
In-Reply-To: <85d07kkh4d.fsf@collabora.com>

On Sun, May 03, 2020 at 02:28:34PM -0400, Gabriel Krisman Bertazi wrote:
> Matthew Wilcox <willy@infradead.org> writes:
> > mapcount is 0, mapping is NULL, refcount is 1, so that's all fine.
> > flags has 'waiters' set, which is not in the allowed list.  I don't
> > know the internals of FUSE, so I don't know why that is.
> 
> Hi
> 
> On the first message, Nikolaus sent the following line:
> 
> >> [ 2333.009937] fuse: page=00000000dd1750e3 index=2022240 flags=17ffffc0000097, count=1,
> >> mapcount=0, mapping=00000000125079ad
> 
> It should be noted that on the second run, where we got the dump_page
> log, it indeed had a null mapping, which is similar to what Nikolaus
> asked on the previous thread he linked to, but looks like this wasn't
> the case on at least some of the reproductions of the issue.  On the
> line above, the condition that triggered the warning was page->mapping
> != NULL.  I don't know what to do with this information, though.

I don't see anything in upstream which will print "NULL" for a null
pointer passed to pointer().  ptr_to_id() doesn't check for NULL, nor
does __ptr_to_hashval().

I think we _should_, along with the ERR_PTR values and values less
than 4096.  But that patch isn't upstream.

  reply	other threads:[~2020-05-03 20:06 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-02 19:09 Nikolaus Rath
2020-05-02 19:52 ` Nikolaus Rath
2020-05-03  3:26   ` Matthew Wilcox
2020-05-03  8:43     ` [fuse-devel] " Nikolaus Rath
2020-05-03 10:27       ` Matthew Wilcox
2020-05-03 18:28         ` Gabriel Krisman Bertazi
2020-05-03 20:06           ` Matthew Wilcox [this message]
2020-05-03 20:25           ` Nikolaus Rath
2020-05-06 13:57             ` Vlastimil Babka
2020-05-03 21:34         ` Hugh Dickins
2020-05-18 12:45         ` Miklos Szeredi
2020-05-18 14:48           ` Matthew Wilcox
2020-05-18 14:58             ` Miklos Szeredi
2020-05-18 15:26               ` Matthew Wilcox
  -- strict thread matches above, loose matches on Subject: below --
2018-12-26 21:43 Nikolaus Rath
2019-01-07  8:28 ` [fuse-devel] " Miklos Szeredi
2019-01-07 21:05   ` Nikolaus Rath
2019-01-08  8:27     ` Miklos Szeredi
2019-01-08 10:35       ` Nikolaus Rath
2019-01-09  8:07         ` Miklos Szeredi
2019-01-11 15:39           ` Nikolaus Rath
2019-01-11 15:39             ` [fuse-devel] " Nikolaus Rath
2019-02-10 22:05             ` Nikolaus Rath
2019-02-12 14:57               ` Miklos Szeredi
2019-02-12 21:28                 ` Nikolaus Rath
2019-02-25 21:41                   ` Nikolaus Rath
2019-02-26 12:57                     ` Miklos Szeredi
2019-02-26 13:30                       ` Miklos Szeredi

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