Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751778AbWIRPdZ (ORCPT ); Mon, 18 Sep 2006 11:33:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751779AbWIRPdY (ORCPT ); Mon, 18 Sep 2006 11:33:24 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:22145 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1751778AbWIRPdX (ORCPT ); Mon, 18 Sep 2006 11:33:23 -0400 Date: Mon, 18 Sep 2006 17:24:58 +0200 From: Ingo Molnar To: Andi Kleen Cc: Linus Torvalds , Andrew Morton , Chuck Ebbert <76306.1226@compuserve.com>, In Cognito , linux-kernel , bcrl@kvack.org Subject: Re: Sysenter crash with Nested Task Bit set Message-ID: <20060918152458.GA13273@elte.hu> References: <200609172354_MC3-1-CB7A-58ED@compuserve.com> <20060917222537.55241d19.akpm@osdl.org> <200609181729.23934.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200609181729.23934.ak@suse.de> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1023 Lines: 25 * Andi Kleen wrote: > > #define switch_to(prev,next,last) do { \ > > unsigned long esi,edi; \ > > - asm volatile("pushl %%ebp\n\t" \ > > + asm volatile("pushfl\n\t" /* Save flags */ \ > > + "pushl %%ebp\n\t" \ > > We used to do that pushfl/popfl some time ago, but Ben removed it > because it was slow on P4. Ok, nobody thought of that case back then. I _should_ have thought of that though, because when this change was done originally i had to reintroduce it both for exec-shield and for -rt, so apparently it must have triggered in certain circumstances - i just didnt notice the reason. (but recent exec-shield and -rt patches dont have this revert, so the condition must have gone away. But it was a long time ago.) Ingo - 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/