From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 4B98B6B01F0 for ; Fri, 27 Aug 2010 17:33:51 -0400 (EDT) Received: from hpaq13.eem.corp.google.com (hpaq13.eem.corp.google.com [172.25.149.13]) by smtp-out.google.com with ESMTP id o7RLXnpY025770 for ; Fri, 27 Aug 2010 14:33:50 -0700 Received: from vws16 (vws16.prod.google.com [10.241.21.144]) by hpaq13.eem.corp.google.com with ESMTP id o7RLXQ1K018136 for ; Fri, 27 Aug 2010 14:33:35 -0700 Received: by vws16 with SMTP id 16so4216686vws.0 for ; Fri, 27 Aug 2010 14:33:35 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20100826235052.GZ6803@random.random> <20100827095546.GC6803@random.random> Date: Fri, 27 Aug 2010 14:33:35 -0700 Message-ID: Subject: Re: [PATCH] mm: fix hang on anon_vma->root->lock From: Hugh Dickins Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: Andrea Arcangeli , Linus Torvalds , Andrew Morton , Rik van Riel , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Sorry, I seem to have hit some key which sent the mail off too soon, a tab perhaps: finishing up... On Fri, Aug 27, 2010 at 2:28 PM, Hugh Dickins wrote: > On Fri, Aug 27, 2010 at 1:56 PM, Christoph Lameter wrote: >> >>> of that second check, then we know that we got the right anon_vma, >> >> I do not see a second check (*after* taking the lock) in the patch if (page_mapped(page)) return anon_vma; >> and the way the lock is taken can be a problem in itself. No, that's what we rely upon SLAB_DESTROY_BY_RCU for. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org