From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 743CCC43387 for ; Thu, 17 Jan 2019 01:26:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AAFD205C9 for ; Thu, 17 Jan 2019 01:26:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727692AbfAQB0v (ORCPT ); Wed, 16 Jan 2019 20:26:51 -0500 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:5204 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbfAQB0u (ORCPT ); Wed, 16 Jan 2019 20:26:50 -0500 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail07.adl2.internode.on.net with ESMTP; 17 Jan 2019 11:56:47 +1030 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1gjwSD-0003Je-SS; Thu, 17 Jan 2019 12:26:45 +1100 Date: Thu, 17 Jan 2019 12:26:45 +1100 From: Dave Chinner To: Linus Torvalds Cc: Dominique Martinet , Jiri Kosina , Matthew Wilcox , Jann Horn , Andrew Morton , Greg KH , Peter Zijlstra , Michal Hocko , Linux-MM , kernel list , Linux API Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged Message-ID: <20190117012645.GU4205@dastard> References: <20190110122442.GA21216@nautica> <20190111020340.GM27534@dastard> <20190111040434.GN27534@dastard> <20190111073606.GP27534@dastard> <20190115234510.GA6173@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 16, 2019 at 04:54:49PM +1200, Linus Torvalds wrote: > On Wed, Jan 16, 2019 at 11:45 AM Dave Chinner wrote: > > > > I'm assuming that you can invalidate the page cache reliably by a > > means that does not repeated require probing to detect invalidation > > has occurred. I've mentioned one method in this discussion > > already... > > Yes. And it was made clear to you that it was a bug in xfs dio and > what the right thing to do was. > > And you ignored that, and claimed it was a feature. Linus, either you aren't listening or you're being intentionally provocative. So, for the *third* time this thread: we can probably remove this code but first we need to be sure it doesn't cause unexpected regressions before we commit such a change. We are not cowboys who test userspace behavioural changes on users without review or discussion. Indeed, I wrote a patch to remove the invalidation /several days ago/ and put it into my test trees, and it's been there since. Just because you don't see immediate changes doesn't mean it isn't happening. > Either you care or you don't. If you don't care (and so far everything > you said seems to imply you don't), Linus, this is just a personal attack and IMO a violation of the CoC. It's straight out wrong, insulting, totally unprofessional and completely uncalled for. This is most definitely not a useful technical response to the issues I raised. i.e you cut out all the context of my response about whether "no probing necessary" page cache invalidation attacks are something we need to care about in the future. We don't need you to shout about existing "no probing necessary" page cache invalidation attacks that are already being addressed, we need to determine if it's going to be a recurring problem in future because that directly affects the mitigation strategies we can implement. -Dave. -- Dave Chinner david@fromorbit.com