From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f52.google.com (mail-pa0-f52.google.com [209.85.220.52]) by kanga.kvack.org (Postfix) with ESMTP id 20A416B0031 for ; Thu, 19 Dec 2013 01:07:04 -0500 (EST) Received: by mail-pa0-f52.google.com with SMTP id ld10so713961pab.11 for ; Wed, 18 Dec 2013 22:07:03 -0800 (PST) Received: from LGEAMRELO01.lge.com (lgeamrelo01.lge.com. [156.147.1.125]) by mx.google.com with ESMTP id sw1si1758295pbc.162.2013.12.18.22.07.01 for ; Wed, 18 Dec 2013 22:07:02 -0800 (PST) Date: Thu, 19 Dec 2013 15:07:03 +0900 From: Joonsoo Kim Subject: Re: [PATCH v3] mm/rmap: fix BUG at rmap_walk Message-ID: <20131219060703.GA27787@lge.com> References: <1387431715-6786-1-git-send-email-liwanp@linux.vnet.ibm.com> <20131219055510.GA27532@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131219055510.GA27532@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Wanpeng Li Cc: Andrew Morton , Sasha Levin , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Dec 19, 2013 at 02:55:10PM +0900, Joonsoo Kim wrote: > On Thu, Dec 19, 2013 at 01:41:55PM +0800, Wanpeng Li wrote: > > This bug is introduced by commit 37f093cdf(mm/rmap: use rmap_walk() in > > page_referenced()). page_get_anon_vma() called in page_referenced_anon() > > will lock and increase the refcount of anon_vma. PageLocked is not required > > by page_referenced_anon() and there is not any assertion before, commit > > 37f093cdf introduced this extra BUG_ON() checking for anon page by mistake. > > This patch fix it by remove rmap_walk()'s VM_BUG_ON() and comment reason why > > the page must be locked for rmap_walk_ksm() and rmap_walk_file(). FYI. See following link to get more information. https://lkml.org/lkml/2004/7/12/241 Thanks. -- 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