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From: Miklos Szeredi <miklos@szeredi.hu>
To: fuse-devel <fuse-devel@lists.sourceforge.net>,
	Miklos Szeredi <mszeredi@redhat.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [fuse-devel] fuse: trying to steal weird page
Date: Mon, 7 Jan 2019 09:28:15 +0100	[thread overview]
Message-ID: <CAJfpegtQic0v+9G7ODXEzgUPAGOz+3Ay28uxqbafZGMJdqL-zQ@mail.gmail.com> (raw)
In-Reply-To: <87o998m0a7.fsf@vostro.rath.org>

On Wed, Dec 26, 2018 at 10:44 PM Nikolaus Rath <Nikolaus@rath.org> wrote:
>
> Hi,
>
> I am seeing relatively regular occurences of
>
> $ sudo dmesg | tail
> [21929.138815] fuse: trying to steal weird page
> [21929.138821]   page=00000000a7dd2617 index=64 flags=17fffc0000000ad, count=1, mapcount=0, mapping=          (null)
> [21930.647338] fuse: trying to steal weird page
> [21930.647345]   page=00000000a07f32af index=2848 flags=17fffc0000000ad, count=1, mapcount=0, mapping=          (null)
> [21932.338873] fuse: trying to steal weird page
> [21932.338879]   page=0000000067e3a012 index=64 flags=17fffc0000000ad, count=1, mapcount=0, mapping=          (null)
> [21933.930703] fuse: trying to steal weird page
> [21933.930710]   page=00000000046feb25 index=845 flags=17fffc0000000ad, count=1, mapcount=0, mapping=          (null)
> [21936.163174] fuse: trying to steal weird page
> [21936.163180]   page=00000000fb80fe27 index=0 flags=17fffc0000000ad, count=1, mapcount=0, mapping=          (null)

The page has the PG_dity and PG_waiters flags set which are
incompatible with stealing.  page_cache_pipe_buf_steal() does
apparently filter out dirty ones, so it's not a regular file that we
are trying to streal the page from.  So the question is: what is the
source of the splice()?

Thanks,
Miklos


>
> They do not seem to correlate with userspace errors.
>
> (I am debugging a mysterious EBADF error that I get from an nftw() walk
> and that disappears when running under strace(), but it its occurence
> does not correlate).
>
>
> What are the implications of the above kernel message? Is there a way to
> provide more debugging information?
>
> $ uname -a
> Linux vostro.rath.org 4.18.0-0.bpo.1-amd64 #1 SMP Debian 4.18.6-1~bpo9+1 (2018-09-13) x86_64 GNU/Linux
>
> Best,
> -Nikolaus
>
> --
> GPG Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F
>
>              »Time flies like an arrow, fruit flies like a Banana.«
>
>
> --
> fuse-devel mailing list
> To unsubscribe or subscribe, visit https://lists.sourceforge.net/lists/listinfo/fuse-devel

  reply	other threads:[~2019-01-07  8:28 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-26 21:43 Nikolaus Rath
2019-01-07  8:28 ` Miklos Szeredi [this message]
2019-01-07 21:05   ` [fuse-devel] " Nikolaus Rath
2019-01-08  8:27     ` Miklos Szeredi
2019-01-08 10:35       ` Nikolaus Rath
2019-01-09  8:07         ` Miklos Szeredi
     [not found]           ` <CAJfpegtiXDgSBWN8MRubpAdJFxy95X21nO_yycCZhpvKLVePRA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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
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
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

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