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: 42+ 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 19:08 ` 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
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