From: Andrew Morton <akpm@linux-foundation.org>
To: Valdis.Kletnieks@vt.edu
Cc: "Vasiliy Kulikov" <segoon@openwall.com>,
"Arkadiusz Miśkiewicz" <a.miskiewicz@gmail.com>,
linux-kernel@vger.kernel.org,
"Alexey Dobriyan" <adobriyan@gmail.com>
Subject: Re: [PATCH] proc: fix mount -t proc -o AAA
Date: Mon, 26 Mar 2012 15:37:38 -0700 [thread overview]
Message-ID: <20120326153738.aa728115.akpm@linux-foundation.org> (raw)
In-Reply-To: <97428.1332714196@turing-police.cc.vt.edu>
On Sun, 25 Mar 2012 18:23:16 -0400
Valdis.Kletnieks@vt.edu wrote:
> On Sun, 25 Mar 2012 19:36:12 +0400, Vasiliy Kulikov said:
> > On Sun, Mar 25, 2012 at 09:24 +0200, Arkadiusz MiE^[kiewicz wrote:
> > > but there is another problem - unmounting it and mounting without options
> > > causes old option to persist:
> > >
> > > # mount none /proc -t proc -o hidepid=2
> > > # umount /proc
> > > # mount none /proc -t proc
> > > # grep "/proc" /proc/mounts
> > > none /proc proc rw,relatime,hidepid=2 0 0
> > >
> > > There should be no hidepid=2 now.
> >
> > No, that's an expected behaviour.
>
> "You keep using that word. I do not think it means what you think it means". ;)
>
> > Procfs is a special filesystem.
>
> And the fact it's "special" makes this *unexpected* behavior. Are there
> any other filesystems where -o values will persist across an unmount
> and then take effect *even if no -o is given* on a subsequent mount?
>
> Yes, it may be what the code actually *does*, but it certainly violates
> the Principle of Least Surprise...
It surprises me ;) I never noticed that before.
It does seem pretty insane. I wonder how much downstream damage would
result from fixing it.
next prev parent reply other threads:[~2012-03-26 22:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-22 8:03 3.3 and hidepid feature problem - options not always applied at mount Arkadiusz Miśkiewicz
2012-03-23 17:10 ` [PATCH] proc: fix mount -t proc -o AAA Vasiliy Kulikov
2012-03-23 18:45 ` Arkadiusz Miśkiewicz
2012-03-23 19:18 ` Vasiliy Kulikov
2012-03-23 23:15 ` Andrew Morton
2012-03-25 7:24 ` Arkadiusz Miśkiewicz
2012-03-25 15:36 ` Vasiliy Kulikov
2012-03-25 17:40 ` Arkadiusz Miśkiewicz
2012-03-25 17:49 ` Vasiliy Kulikov
2012-03-25 22:23 ` Valdis.Kletnieks
2012-03-26 22:37 ` Andrew Morton [this message]
2012-03-31 13:55 ` [PATCH] proc: reset mount options after the last procfs umount Vasiliy Kulikov
2012-03-31 14:19 ` Arkadiusz Miśkiewicz
2012-03-31 15:20 ` Vasiliy Kulikov
2012-03-31 15:31 ` Arkadiusz Miśkiewicz
2012-03-31 15:46 ` Vasiliy Kulikov
2012-03-26 22:35 ` [PATCH] proc: fix mount -t proc -o AAA Andrew Morton
2012-03-25 15:27 ` Vasiliy Kulikov
2012-03-31 13:51 ` Vasiliy Kulikov
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