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From: Nikolaus Rath <Nikolaus@rath.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org,
	fuse-devel <fuse-devel@lists.sourceforge.net>,
	linux-mm <linux-mm@kvack.org>, miklos <mszeredi@redhat.com>,
	"Gabriel Krisman Bertazi" <krisman@collabora.com>,
	"André Almeida" <andrealmeid@collabora.com>
Subject: Re: [fuse-devel] fuse: trying to steal weird page
Date: Sun, 03 May 2020 09:43:41 +0100	[thread overview]
Message-ID: <87368hz9vm.fsf@vostro.rath.org> (raw)
In-Reply-To: <20200503032613.GE29705@bombadil.infradead.org> (Matthew Wilcox's message of "Sat, 2 May 2020 20:26:13 -0700")

On May 02 2020, Matthew Wilcox <willy@infradead.org> wrote:
> On Sat, May 02, 2020 at 08:52:48PM +0100, Nikolaus Rath wrote:
>> On May 02 2020, Nikolaus Rath <Nikolaus@rath.org> wrote:
>> > I have recently noticed that a FUSE filesystem regularly produces many
>> > kernel messages like this:
>> >
>> > [ 2333.009931] fuse: trying to steal weird page
>> > [ 2333.009937] fuse: page=00000000dd1750e3 index=2022240 flags=17ffffc0000097, count=1,
>> > mapcount=0, mapping=00000000125079ad
> ...
>> > What are the implications of the above kernel message? Is there a way to
>> > provide more debugging information?
>
> It'd be helpful to use the common debugging infrastructure which prints
> more useful information:
>
> +++ b/fs/fuse/dev.c
> @@ -772,8 +772,7 @@ static int fuse_check_page(struct page *page)
>                1 << PG_lru |
>                1 << PG_active |
>                1 << PG_reclaim))) {
> -               pr_warn("trying to steal weird page\n");
> -               pr_warn("  page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
> +               dump_page(page, "fuse: trying to steal weird page");
>                 return 1;
>         }
>         return 0;
>
> (whitespace damaged; if you can't make the equivalent change, let me
> know and I'll send you a real patch)

Here's what I got:

[  221.277260] page:ffffec4bbd639880 refcount:1 mapcount:0 mapping:0000000000000000 index:0xd9
[  221.277265] flags: 0x17ffffc0000097(locked|waiters|referenced|uptodate|lru)
[  221.277269] raw: 0017ffffc0000097 ffffec4bbd62f048 ffffec4bbd619308 0000000000000000
[  221.277271] raw: 00000000000000d9 0000000000000000 00000001ffffffff ffff9aec11beb000
[  221.277272] page dumped because: fuse: trying to steal weird page
[  221.277273] page->mem_cgroup:ffff9aec11beb000
[  221.601910] page:ffffec4bbd4b2dc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x1273
[  221.601915] flags: 0x17ffffc0000097(locked|waiters|referenced|uptodate|lru)
[  221.601919] raw: 0017ffffc0000097 ffffec4bbd51f488 ffffec4bbd4b2d48 0000000000000000
[  221.601921] raw: 0000000000001273 0000000000000000 00000001ffffffff ffff9aec11beb000
[  221.601922] page dumped because: fuse: trying to steal weird page
[  221.601923] page->mem_cgroup:ffff9aec11beb000
[  221.958699] page:ffffec4bbd424d80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x38be
[  221.958703] flags: 0x17ffffc0000097(locked|waiters|referenced|uptodate|lru)
[  221.958707] raw: 0017ffffc0000097 ffffec4bbd424048 ffffec4bbd424d48 0000000000000000
[  221.958709] raw: 00000000000038be 0000000000000000 00000001ffffffff ffff9aec11beb000
[  221.958710] page dumped because: fuse: trying to steal weird page
[  221.958711] page->mem_cgroup:ffff9aec11beb000



Best,
-Nikolaus
-- 
GPG Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F

             »Time flies like an arrow, fruit flies like a Banana.«

  reply	other threads:[~2020-05-03  8:44 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     ` Nikolaus Rath [this message]
2020-05-03 10:27       ` [fuse-devel] " 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
  -- 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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