From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752112Ab1HEU1C (ORCPT ); Fri, 5 Aug 2011 16:27:02 -0400 Received: from one.firstfloor.org ([213.235.205.2]:57486 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751405Ab1HEU1A (ORCPT ); Fri, 5 Aug 2011 16:27:00 -0400 Date: Fri, 5 Aug 2011 22:26:56 +0200 From: Andi Kleen To: "H. Peter Anvin" Cc: Andi Kleen , luto@mit.edu, x86@kernel.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, lueckintel@yahoo.com, kimwooyoung@gmail.com Subject: Re: New vsyscall emulation breaks JITs Message-ID: <20110805202656.GI5782@one.firstfloor.org> References: <20110805200945.GA14014@tassilo.jf.intel.com> <4E3C5154.2050307@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E3C5154.2050307@zytor.com> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I have to say I believe that trying to JIT the vdso or vsyscall pages is > extremely dubious at best. They are fundamentally different from normal > user space in that the kernel can muck with them any time, without > notifying userspace about it. The other aspect of this is that this is > about the legacy vsyscall page, which we're trying to get rid of, partly > because of security problems. There's clear evidence now you can't: it's used even by new binaries. -Andi