From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Andi Kleen <andi@firstfloor.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH] x86: Fix AMD K6 indirect call check v2
Date: Sun, 21 Apr 2013 15:35:41 -0700 [thread overview]
Message-ID: <517469BD.3060406@zytor.com> (raw)
In-Reply-To: <20130421174456.GA4559@pd.tnic>
On 04/21/2013 10:44 AM, Borislav Petkov wrote:
>
> But I have hard time understanding what that test with the 10^6 loop
> iterations is supposed to achieve. And what makes sure that the RDTSCs
> don't get reordered? Or maybe K6 wasn't reordering that aggressively...
>
> Erratum says "unpredictable system behavior" but it seems it wasn't that
> unpredictable after all - otherwise the fix would've been "HLT" right
> then and there. :)
>
Looks like it is just trying to sense the bug... but then it doesn't
actually do anything about it. At least it should taint the kernel.
-hpa
next prev parent reply other threads:[~2013-04-21 22:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-21 16:49 [PATCH] x86: Fix AMD K6 indirect call check v2 Andi Kleen
2013-04-21 17:06 ` H. Peter Anvin
2013-04-21 17:13 ` Andi Kleen
2013-04-21 17:44 ` Borislav Petkov
2013-04-21 22:35 ` H. Peter Anvin [this message]
2013-04-21 22:48 ` Borislav Petkov
2013-04-22 11:25 ` Wolfram Gloger
2013-04-22 12:58 ` Ondrej Zary
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