From: Steffen Klassert <steffen.klassert@secunet.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Alexey Dobriyan <adobriyan@gmail.com>,
linux-crypto@vger.kernel.org, netdev@vger.kernel.org,
ken@codelabs.ch
Subject: Re: sha512: make it work, undo percpu message schedule
Date: Fri, 13 Jan 2012 12:02:55 +0100 [thread overview]
Message-ID: <20120113110255.GD12501@secunet.com> (raw)
In-Reply-To: <1326450942.2272.20.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
On Fri, Jan 13, 2012 at 11:35:42AM +0100, Eric Dumazet wrote:
> Le vendredi 13 janvier 2012 à 18:08 +1100, Herbert Xu a écrit :
> > On Fri, Jan 13, 2012 at 02:55:14AM +0300, Alexey Dobriyan wrote:
> > >
> > > Herbert, I couldn't come up with a single scenario. :-(
> > > But the bug is easy to reproduce.
> >
> > OK, does this patch work for you?
> >
> > commit 31f4e55c09c1170f8b813c14b1299b70f50db414
> > Author: Herbert Xu <herbert@gondor.apana.org.au>
> > Date: Fri Jan 13 18:06:50 2012 +1100
> >
> > crypto: sha512 - Fix msg_schedule race
> >
> > The percpu msg_schedule setup was unsafe as a user in a process
> > context can be interrupted by a softirq user which would then
> > scribble over the exact same work area. This was discovered by
> > Steffen Klassert.
> >
> > This patch based on ideas from Eric Dumazet fixes this by using
> > two independent work areas.
> >
> > Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
> > Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
> >
>
> I wonder ...
>
> With 4096 cpus, do we really want to reserve 5242880 bytes of memory for
> this function ?
>
> What about following patch instead ?
>
> (Trying a dynamic memory allocation, and fallback on a single
> pre-allocated bloc of memory, shared by all cpus, protected by a
> spinlock)
If we want to do dynamic memory allocation, we could place it to the
shash_desc context where we already store the intermediate digest value.
This is preallocated anyway, so we don't need to do another allocation.
next prev parent reply other threads:[~2012-01-13 11:02 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-11 0:00 sha512: make it work, undo percpu message schedule Alexey Dobriyan
2012-01-11 0:12 ` Alexey Dobriyan
2012-01-11 0:36 ` Herbert Xu
2012-01-12 23:55 ` Alexey Dobriyan
2012-01-13 0:19 ` Herbert Xu
2012-01-13 7:08 ` Herbert Xu
2012-01-13 10:35 ` Eric Dumazet
2012-01-13 10:41 ` Eric Dumazet
2012-01-13 10:57 ` Eric Dumazet
2012-01-13 11:33 ` Alexey Dobriyan
2012-01-13 12:34 ` Eric Dumazet
2012-01-14 18:20 ` Alexey Dobriyan
2012-01-14 18:27 ` [PATCH 1/3] " Alexey Dobriyan
2012-01-14 18:40 ` [PATCH 2/3] sha512: reduce stack usage to safe number Alexey Dobriyan
2012-01-14 18:44 ` [PATCH 3/3] sha512: use standard ror64() Alexey Dobriyan
2012-01-14 19:08 ` [PATCH 2/3] sha512: reduce stack usage to safe number Linus Torvalds
2012-01-14 20:41 ` Alexey Dobriyan
2012-01-14 21:14 ` Linus Torvalds
2012-01-16 9:56 ` David Laight
2012-01-16 10:20 ` Alexey Dobriyan
2012-01-16 10:23 ` Eric Dumazet
2012-01-16 11:37 ` David Laight
2012-01-17 12:03 ` Alexey Dobriyan
2012-01-18 18:02 ` [PATCH 4/3] sha512: reduce stack usage even on i386 Alexey Dobriyan
2012-01-26 2:35 ` Herbert Xu
2012-01-27 17:51 ` Alexey Dobriyan
2012-01-27 22:32 ` Herbert Xu
2012-01-30 11:10 ` Alexey Dobriyan
2012-02-03 3:34 ` Herbert Xu
2012-01-14 21:46 ` [PATCH 1/3] sha512: make it work, undo percpu message schedule Eric Dumazet
2012-01-14 21:52 ` Linus Torvalds
2012-01-14 22:00 ` Eric Dumazet
2012-01-15 1:43 ` Herbert Xu
2012-01-13 11:02 ` Steffen Klassert [this message]
2012-01-15 1:43 ` Herbert Xu
2012-01-13 11:45 ` David Laight
2012-01-13 12:35 ` Eric Dumazet
2012-01-13 6:22 ` Steffen Klassert
2012-01-13 6:46 ` Herbert Xu
2012-01-13 6:48 ` Eric Dumazet
2012-01-13 6:50 ` Herbert Xu
2012-01-13 9:45 ` David Laight
2012-01-11 1:12 ` Adrian-Ken Rueegsegger
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=20120113110255.GD12501@secunet.com \
--to=steffen.klassert@secunet.com \
--cc=adobriyan@gmail.com \
--cc=eric.dumazet@gmail.com \
--cc=herbert@gondor.apana.org.au \
--cc=ken@codelabs.ch \
--cc=linux-crypto@vger.kernel.org \
--cc=netdev@vger.kernel.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.