Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932214Ab2BWWjF (ORCPT ); Thu, 23 Feb 2012 17:39:05 -0500 Received: from mail-ww0-f44.google.com ([74.125.82.44]:42368 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932095Ab2BWWjD (ORCPT ); Thu, 23 Feb 2012 17:39:03 -0500 MIME-Version: 1.0 In-Reply-To: <20120223222733.GB1306@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> <20120223222733.GB1306@1wt.eu> From: Linus Torvalds Date: Thu, 23 Feb 2012 14:38:42 -0800 X-Google-Sender-Auth: MUv2wC4eu_t5m_psa9KBV1wMrN0 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: 1206 Lines: 33 On Thu, Feb 23, 2012 at 2:27 PM, Willy Tarreau wrote: > > OK so indeed I will only be able to check that it boots :-/ Well, we could do some trivial test-harness that just forces the issue with regular timer interrupts (and even without AES-NI). I think Peter talked about that when we were trying to hunt it down - but I think he was then able to reproduce the problem without anything special and we dropped it. Essentially, just doing something like if (irq_fpu_usable()) { kernel_fpu_begin(); kernel_fpu_end(); } in do_irq() and do_softirq() would stress-test things even without wireless, and even without AES-NI. You'd still need an x86-32 machine to test on, because x86-64 was immune to this issue. But yeah, the impact of this seems to be small enough that for older kernels (which are likely used on older systems for maintenance anyway) disabling AES-NI on x86-32 really might be the way to go. 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/