linux-kernel - Re: Question for remount

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20090224085724.4cc1b3b2.kamezawa.hiroyu@jp.fujitsu.com>
Date:	Tue, 24 Feb 2009 08:57:24 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	Li Zefan <lizf@...fujitsu.com>
Cc:	Paul Menage <menage@...gle.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	containers@...ts.linux-foundation.org
Subject: Re: Question for remount

On Mon, 23 Feb 2009 10:32:46 +0800
Li Zefan <lizf@...fujitsu.com> wrote:

> KAMEZAWA Hiroyuki wrote:
> > Paul Menage さんは書きました：
> >> On Fri, Feb 20, 2009 at 2:02 AM, KAMEZAWA Hiroyuki
> >> <kamezawa.hiroyu@...fujitsu.com> wrote:
> >>> 2. /proc/mounts information of release_agent should be updated....
> >>>   when it's overwritten directly.
> >> Yes, definitely. But shouldn't that happen already?
> >> cgroup_show_options() reports the current value of
> >> root->release_agent_path in /proc/mounts. Is it possible that mount is
> >> actually storing/retrieving this information in /etc/mtab, which
> >> doesn't get updated?
> >>
> > Ah, you're right. /proc/mounts is updated but /etc/mtab is not updated.
> > Hmm..from man mount(1), /etc/mtab is not synchronized with /proc/mounts.
> > Do we need to allow release_agent override at remount ?
> > 
> 
> Since we've allowed this behavior, I think we shouldn't disallow it to
> supprise users?
> 
In a bit different stroy, it already surprises a user (me).
for example)

#mount -t cgroup none /cgroups -ocpu,release_agent=hogehoge
#mount -oremount,cpuacct /cgroups,release_agent=xxxx
=> remount fails. because the option "release_agent" appears twice.

#mount -t cgroup none /cgroups -ocpu,release_agent=hogehoge
#mount -t cgroup none /cgroups -oremount,cpuacct /cgroups,release_agent=xxxx
=> remount success.

At least, updating documentation to notice this is necessary I think.


-Kame

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/