From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752692AbcFBARh (ORCPT ); Wed, 1 Jun 2016 20:17:37 -0400 Received: from www.sr71.net ([198.145.64.142]:46618 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752010AbcFBARc (ORCPT ); Wed, 1 Jun 2016 20:17:32 -0400 Subject: Re: [PATCH 5/8] x86, pkeys: allocation/free syscalls To: mtk.manpages@gmail.com References: <20160531152814.36E0B9EE@viggo.jf.intel.com> <20160531152822.FE8D405E@viggo.jf.intel.com> <20160601123705.72a606e7@lwn.net> <574F386A.8070106@sr71.net> Cc: Jonathan Corbet , lkml , "x86@kernel.org" , Linux API , linux-arch , "linux-mm@kvack.org" , Linus Torvalds , Andrew Morton , Dave Hansen From: Dave Hansen Message-ID: <574F7B16.4080906@sr71.net> Date: Wed, 1 Jun 2016 17:17:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/01/2016 05:11 PM, Michael Kerrisk (man-pages) wrote: >>> >> >>> >> If I read this right, it doesn't actually remove any pkey restrictions >>> >> that may have been applied while the key was allocated. So there could be >>> >> pages with that key assigned that might do surprising things if the key is >>> >> reallocated for another use later, right? Is that how the API is intended >>> >> to work? >> > >> > Yeah, that's how it works. >> > >> > It's not ideal. It would be _best_ if we during mm_pkey_free(), we >> > ensured that no VMAs under that mm have that vma_pkey() set. But, that >> > search would be potentially expensive (a walk over all VMAs), or would >> > force us to keep a data structure with a count of all the VMAs with a >> > given key. >> > >> > I should probably discuss this behavior in the manpages and address it > s/probably// > > And, did I miss it. Was there an updated man-pages patch in the latest > series? I did not notice it. There have been to changes to the patches that warranted updating the manpages until now. I'll send the update immediately.