Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755735Ab2BWWMM (ORCPT ); Thu, 23 Feb 2012 17:12:12 -0500 Received: from mail-wi0-f174.google.com ([209.85.212.174]:46874 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752784Ab2BWWMK (ORCPT ); Thu, 23 Feb 2012 17:12:10 -0500 MIME-Version: 1.0 In-Reply-To: <20120223215242.GA1306@1wt.eu> References: <20120222211928.GA4448@kroah.com> <20120222213253.GA25150@kroah.com> <20120223200905.GA5475@kroah.com> <4F46A1C4.90506@zytor.com> <20120223204832.GA30322@kroah.com> <4F46A6EC.8050804@zytor.com> <20120223211016.GA16275@kroah.com> <20120223215242.GA1306@1wt.eu> From: Linus Torvalds Date: Thu, 23 Feb 2012 14:11:48 -0800 X-Google-Sender-Auth: AoSNS0Pc-eE2U24L5OhLla-psnA Message-ID: Subject: Re: [PATCH 0/5] i387: stable kernel backport To: Willy Tarreau Cc: Greg Kroah-Hartman , "H. Peter Anvin" , stable@vger.kernel.org, Raphael Prevost , Suresh Siddha , Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1333 Lines: 31 On Thu, Feb 23, 2012 at 1:52 PM, Willy Tarreau wrote: > > I would test this too, but apart from ensuring my kernel still boots, > how do I ensure the patches do really fix what the ought to fix ? I > must admit I didn't catch the initial issue they were supposed to fix > unfortunately :-/ Almost nobody did. This only happens on modern CPU's that support the new AES-NI instructions, and only with a 32-bit kernel (although the very unlikely preemption issues can happen on x86-64 too). And you need to have the AES instructions called from interrupts, which probably only happens with the mac80211 wireless networking stack. And even then you need WPA2 to trigger it (I guess AES is sometimes used with "extended WPA1" too, but I dunno). So it's not impossible to trigger, but you do need to have a fairly recent CPU that happily runs in 64-bit mode, and install a 32-bit system on it. And it needs to use the right wireless setup. It's possible that the right solution for really older kernels is just to say that AES_NI depends on X86_64. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/