From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from outbound-smtp01.blacknight.com ([81.17.249.7]:58131 "EHLO outbound-smtp01.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752471AbbH1O6H (ORCPT ); Fri, 28 Aug 2015 10:58:07 -0400 Received: from mail.blacknight.com (pemlinmail02.blacknight.ie [81.17.254.11]) by outbound-smtp01.blacknight.com (Postfix) with ESMTPS id 8F7D1C00DB for ; Fri, 28 Aug 2015 14:50:10 +0000 (UTC) Date: Fri, 28 Aug 2015 15:50:08 +0100 From: Mel Gorman To: Hugh Dickins Cc: akpm@linux-foundation.org, andreyknvl@google.com, cesarb@cesarb.net, dvyukov@google.com, glider@google.com, hannes@cmpxchg.org, jason.low2@hp.com, kcc@google.com, mhocko@suse.cz, stable@vger.kernel.org, vdavydov@parallels.com, mm-commits@vger.kernel.org Subject: Re: [merged] mm-fix-potential-data-race-in-sys_swapon.patch removed from -mm tree Message-ID: <20150828145008.GU12432@techsingularity.net> References: <55db655e.XTdwqaUcB8S3Ntcu%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: On Mon, Aug 24, 2015 at 12:46:54PM -0700, Hugh Dickins wrote: > Adding Mel to Cc. > > On Mon, 24 Aug 2015, akpm@linux-foundation.org wrote: > > > > The patch titled > > Subject: mm: fix potential data race in SyS_swapon > > has been removed from the -mm tree. Its filename was > > mm-fix-potential-data-race-in-sys_swapon.patch > > > > This patch was dropped because it was merged into mainline or a subsystem tree > > Administrative error? I don't see this merged into mainline yet, > and didn't see your usual mail when you send in a batch to Linus. > > And I wouldn't want it rushed too quickly to Linus: that stable > tag is barely justified, this is a very narrow race window that > has gone unnoticed for years, and swapon requires CAP_SYS_ADMIN. > > But also I spotted Mel proposing a swap-over-NFS patch in this area > on LKML last Thursday: he appeared to be relying on the loop that I > remove here, so he might want to veto this one (though can always > reinstate what he needs later, if that's how it plays out). > I don't think we will have a problem. The swap-over-NFS patch collides with yours but not in a way that matters. I'll see how things look after the merge window but I think I'll be able to limit the scope of the lock further and still avoid the use of i_mutex. -- Mel Gorman SUSE Labs