linux-kernel - Re: [PATCH] synchronize

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: <1192743305.7367.11.camel@pasglop>
Date:	Fri, 19 Oct 2007 07:35:05 +1000
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: [PATCH] synchronize_irq needs a barrier


On Thu, 2007-10-18 at 22:35 +0800, Herbert Xu wrote:
> Benjamin Herrenschmidt <benh@...nel.crashing.org> wrote:
> > 
> > Note that some kind of read barrier or compiler barrier should be needed
> > regardless, or we are just not sync'ing with anything at all (we may
> > have loaded the value ages ago and thus operate on a totally stale
> > value). I prefer a full barrier to also ensure all previous stores are
> > pushed out.
> 
> We already have a compiler barrier there in the form of cpu_relax.

Isn't it too late ? The barrier should be before the test_bit, to
prevent it from moving up.

Ben.
 

-
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/