Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758833AbYFREmx (ORCPT ); Wed, 18 Jun 2008 00:42:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752718AbYFREmn (ORCPT ); Wed, 18 Jun 2008 00:42:43 -0400 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:45293 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752629AbYFREmm (ORCPT ); Wed, 18 Jun 2008 00:42:42 -0400 Date: Wed, 18 Jun 2008 13:41:28 +0900 From: Daisuke Nishimura To: KOSAKI Motohiro Cc: Andrew Morton , Rik van Riel , Lee Schermerhorn , Nick Piggin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org Subject: Re: [PATCH][RFC] fix kernel BUG at mm/migrate.c:719! in 2.6.26-rc5-mm3 Message-Id: <20080618134128.828156bc.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20080618105400.b9f1b664.nishimura@mxp.nes.nec.co.jp> References: <20080611225945.4da7bb7f.akpm@linux-foundation.org> <20080617163501.7cf411ee.nishimura@mxp.nes.nec.co.jp> <20080618003129.DE27.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080618105400.b9f1b664.nishimura@mxp.nes.nec.co.jp> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1442 Lines: 44 On Wed, 18 Jun 2008 10:54:00 +0900, Daisuke Nishimura wrote: > On Wed, 18 Jun 2008 00:33:18 +0900, KOSAKI Motohiro wrote: > > > @@ -715,13 +725,7 @@ unlock: > > > * restored. > > > */ > > > list_del(&page->lru); > > > - if (!page->mapping) { > > > - VM_BUG_ON(page_count(page) != 1); > > > - unlock_page(page); > > > - put_page(page); /* just free the old page */ > > > - goto end_migration; > > > - } else > > > - unlock = putback_lru_page(page); > > > + unlock = putback_lru_page(page); > > > } > > > > > > if (unlock) > > > > this part is really necessary? > > I tryed to remove it, but any problem doesn't happend. > > > I made this part first, and added a fix for migration_entry_wait later. > > So, I haven't test without this part, and I think it will cause > VM_BUG_ON() here without this part. > > Anyway, I will test it. > I got this VM_BUG_ON() as expected only by doing: # echo $$ >/cgroup/cpuset/02/tasks So, I beleive that both fixes for migration_entry_wait and unmap_and_move (and, of course, removal VM_BUG_ON from putback_lru_page) are needed. Thanks, Daisuke Nishimura. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/