This message generated a parse failure. Raw output follows here. Please use 'back' to navigate. From devnull@lkml.org Wed Apr 24 09:56:21 2024 Delivery-date: Tue, 27 Mar 2012 00:37:50 +0200 Received: from mail.linuxfoundation.org ([140.211.169.12]:36020 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751431Ab2CZWhj convert rfc822-to-8bit (ORCPT ); Mon, 26 Mar 2012 18:37: Received: from akpm.mtv.corp.google.com (216-239-45-4.google.com [216.239.45.4]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 1D7ED6C9; Mon, 26 Mar 2012 22:37:39 +0000 (UTC) Date: Mon, 26 Mar 2012 15:37:38 -0700 From: Andrew Morton To: Valdis.Kletnieks@vt.edu Cc: Vasiliy Kulikov , Arkadiusz =?UTF-8?Q?Mi=C5=9Bkie?= =?ISO-8859-1?Q?wicz?= , linux-kernel@vger.kernel.org, Alexey Dobriyan Subject: Re: [PATCH] proc: fix mount -t proc -o AAA Message-Id: <20120326153738.aa728115.akpm@linux-foundation.org> In-Reply-To: <97428.1332714196@turing-police.cc.vt.edu> References: <201203220903.15360.a.miskiewicz@gmail.com> <20120323171058.GA3279@albatros> <20120323161504.dced28b9.akpm@linux-foundation.org> <201203250924.06908.a.miskiewicz@gmail.com> <20120325153612.GC4391@albatros> <97428.1332714196@turing-police.cc.vt.edu> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-Id: X-Mailing-List: linux-kernel@vger.kernel.org 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 MiEkiewicz 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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/