From: Linus Torvalds <torvalds@linux-foundation.org>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Vasiliy Kulikov <segoon@openwall.com>,
Andrew Morton <akpm@linux-foundation.org>,
kernel-hardening@lists.openwall.com, Kees Cook <kees@ubuntu.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Christoph Lameter <cl@linux-foundation.org>,
Matt Mackall <mpm@selenic.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Dan Rosenberg <drosenberg@vsecurity.com>,
Theodore Tso <tytso@mit.edu>, Alan Cox <alan@linux.intel.com>,
Jesper Juhl <jj@chaosbits.net>
Subject: Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo
Date: Mon, 19 Sep 2011 11:55:42 -0700 [thread overview]
Message-ID: <CA+55aFwnxOvkS12i97kJcWFrH7n591vxq7vBXKzuROiirnYJ0g@mail.gmail.com> (raw)
In-Reply-To: <CAOJsxLFdNVnW6Faap0UaqZQDQxbA_dEiR2HGdzZtGMJFsVR1WQ@mail.gmail.com>
On Mon, Sep 19, 2011 at 11:46 AM, Pekka Enberg <penberg@cs.helsinki.fi> wrote:
>
> OK, so what about /proc/meminfo, sysfs, 'perf kmem', and other kernel interfaces
> through which you can get direct or indirect information about kernel memory
> allocations?
Pekka, there are degrees of badness.
Also, quite frankly, your argument that /proc/slabinfo is so important
for kernel debugging is bogus. Every time I've complained about the
fact that the thing is useless AND ACTIVELY MISLEADING because it
mixes up all the slabs (so big numbers for "vm_area_struct" might
actually be about some other slab entirely, and *has* been, to the
point of people wasting time), the answer has been "whatever".
You can't have it both ways just to argue for the status quo.
Considering how useless /proc/slabinfo actually is today - exactly
because of the misleading mixing - I suspect the right thing to do is
to make it root-only.
Having some aggregate number in /proc/meminfo would probably be fine.
And yes, we probably should avoid giving page-level granularity in
/proc/meminfo too. Do it in megabytes instead. None of the information
there is really relevant at a page level, everybody just wants rough
aggregates.
Linus
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next prev parent reply other threads:[~2011-09-19 18:56 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20110910164001.GA2342@albatros>
2011-09-10 16:41 ` Vasiliy Kulikov
2011-09-12 15:06 ` Cyrill Gorcunov
2011-09-13 6:28 ` Vasiliy Kulikov
2011-09-14 13:16 ` Vasiliy Kulikov
2011-09-14 15:18 ` Dave Hansen
2011-09-14 15:42 ` [kernel-hardening] " Vasiliy Kulikov
2011-09-14 15:48 ` Vasiliy Kulikov
2011-09-14 18:24 ` Dave Hansen
2011-09-14 18:41 ` Dave Hansen
2011-09-14 19:14 ` Vasiliy Kulikov
2011-09-14 19:27 ` Kees Cook
2011-09-18 17:05 ` [kernel-hardening] " Vasiliy Kulikov
2011-09-19 13:42 ` Christoph Lameter
2011-09-19 14:30 ` Pekka Enberg
2011-09-19 14:46 ` Vasiliy Kulikov
2011-09-19 15:13 ` Pekka Enberg
2011-09-19 15:57 ` Vasiliy Kulikov
2011-09-19 16:11 ` Pekka Enberg
2011-09-19 16:18 ` Vasiliy Kulikov
2011-09-19 17:31 ` Pekka Enberg
2011-09-19 17:35 ` Vasiliy Kulikov
2011-09-19 17:51 ` Christoph Lameter
2011-09-19 19:59 ` Valdis.Kletnieks
2011-09-19 20:02 ` Christoph Lameter
2011-09-19 20:36 ` Valdis.Kletnieks
2011-09-19 17:51 ` Pekka Enberg
2011-09-19 17:58 ` Vasiliy Kulikov
2011-09-19 18:46 ` Pekka Enberg
2011-09-19 18:55 ` Vasiliy Kulikov
2011-09-19 19:20 ` Pekka Enberg
2011-09-19 19:33 ` Pekka Enberg
2011-09-19 18:55 ` Linus Torvalds [this message]
2011-09-19 19:18 ` Pekka Enberg
2011-09-19 19:45 ` Pekka Enberg
2011-09-19 20:59 ` David Rientjes
2011-09-19 18:03 ` Dave Hansen
2011-09-19 18:21 ` Pekka Enberg
2011-09-19 19:45 ` Valdis.Kletnieks
2011-09-19 19:55 ` Alan Cox
2011-09-21 17:05 ` Vasiliy Kulikov
2011-09-22 2:20 ` Valdis.Kletnieks
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