From: Aristeu Rozanski <aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
James Morris <jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org>,
Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>,
Serge Hallyn
<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>,
Jiri Slaby <jslaby-AlSwsSmVLrQ@public.gmane.org>,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] device_cgroup: fix unchecked cgroup parent usage
Date: Thu, 1 Nov 2012 09:28:38 -0400 [thread overview]
Message-ID: <20121101132837.GE14789@redhat.com> (raw)
In-Reply-To: <20121031163501.79a0950e.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
On Wed, Oct 31, 2012 at 04:35:01PM -0700, Andrew Morton wrote:
> On Wed, 31 Oct 2012 12:04:30 -0400
> Aristeu Rozanski <aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>
> > In 4cef7299b4786879a3e113e84084a72b24590c5b the cgroup parent usage is
> > unchecked. root will not have a parent and trying to use
> > device.{allow,deny} will cause problems.
>
> From my reading of the code "problems" means "kernel null pointer
> dereference".
yes. you want me to resubmit it fixing it or you want to update it?
> > static inline int may_allow_all(struct dev_cgroup *parent)
>
> offtopic: this function could quite neatly have a bool return type.
ok, will do.
> > {
> > + if (!parent)
> > + return 1;
>
> hm. Does it need a comment explaining what and why? I guess not... just.
it's because the root's parent has to always allows full access to all
devices. I can add a comment when I turn into a bool if you want.
--
Aristeu
WARNING: multiple messages have this Message-ID (diff)
From: Aristeu Rozanski <aris@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Li Zefan <lizefan@huawei.com>, James Morris <jmorris@namei.org>,
Pavel Emelyanov <xemul@openvz.org>,
Serge Hallyn <serge.hallyn@canonical.com>,
Jiri Slaby <jslaby@suse.cz>,
cgroups@vger.kernel.org
Subject: Re: [PATCH] device_cgroup: fix unchecked cgroup parent usage
Date: Thu, 1 Nov 2012 09:28:38 -0400 [thread overview]
Message-ID: <20121101132837.GE14789@redhat.com> (raw)
In-Reply-To: <20121031163501.79a0950e.akpm@linux-foundation.org>
On Wed, Oct 31, 2012 at 04:35:01PM -0700, Andrew Morton wrote:
> On Wed, 31 Oct 2012 12:04:30 -0400
> Aristeu Rozanski <aris@redhat.com> wrote:
>
> > In 4cef7299b4786879a3e113e84084a72b24590c5b the cgroup parent usage is
> > unchecked. root will not have a parent and trying to use
> > device.{allow,deny} will cause problems.
>
> From my reading of the code "problems" means "kernel null pointer
> dereference".
yes. you want me to resubmit it fixing it or you want to update it?
> > static inline int may_allow_all(struct dev_cgroup *parent)
>
> offtopic: this function could quite neatly have a bool return type.
ok, will do.
> > {
> > + if (!parent)
> > + return 1;
>
> hm. Does it need a comment explaining what and why? I guess not... just.
it's because the root's parent has to always allows full access to all
devices. I can add a comment when I turn into a bool if you want.
--
Aristeu
next prev parent reply other threads:[~2012-11-01 13:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-31 16:04 [PATCH] device_cgroup: fix unchecked cgroup parent usage Aristeu Rozanski
2012-10-31 16:23 ` Tejun Heo
[not found] ` <20121031160430.GD14789-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-10-31 17:21 ` Serge Hallyn
2012-10-31 17:21 ` Serge Hallyn
2012-10-31 23:35 ` Andrew Morton
2012-10-31 23:35 ` Andrew Morton
[not found] ` <20121031163501.79a0950e.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2012-11-01 13:28 ` Aristeu Rozanski [this message]
2012-11-01 13:28 ` Aristeu Rozanski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121101132837.GE14789@redhat.com \
--to=aris-h+wxahxf7alqt0dzr+alfa@public.gmane.org \
--cc=akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org \
--cc=cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org \
--cc=jslaby-AlSwsSmVLrQ@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org \
--cc=serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org \
--cc=tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
--cc=xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.