From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ea0-f178.google.com (mail-ea0-f178.google.com [209.85.215.178]) by kanga.kvack.org (Postfix) with ESMTP id 9F9856B0038 for ; Tue, 11 Mar 2014 15:40:49 -0400 (EDT) Received: by mail-ea0-f178.google.com with SMTP id a15so4499478eae.23 for ; Tue, 11 Mar 2014 12:40:49 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id y41si9762134eel.104.2014.03.11.12.40.47 for ; Tue, 11 Mar 2014 12:40:48 -0700 (PDT) Date: Tue, 11 Mar 2014 14:43:53 -0400 From: Dave Jones Subject: Re: [PATCH] mm: remove BUG_ON() from mlock_vma_page() Message-ID: <20140311184353.GA10764@redhat.com> References: <1387327369-18806-1-git-send-email-bob.liu@oracle.com> <20140131123352.a3da2a1dee32d79ad1f6af9f@linux-foundation.org> <530A4CBE.5090305@oracle.com> <6B2BA408B38BA1478B473C31C3D2074E2F6DBA97C6@SV-EXCHANGE1.Corp.FC.LOCAL> <5314A9E9.6090802@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5314A9E9.6090802@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Motohiro Kosaki , Sasha Levin , Andrew Morton , Bob Liu , "linux-mm@kvack.org" , "walken@google.com" , Motohiro Kosaki JP , "riel@redhat.com" , "stable@kernel.org" , "gregkh@linuxfoundation.org" , Bob Liu On Mon, Mar 03, 2014 at 05:12:25PM +0100, Vlastimil Babka wrote: > >> On 01/31/2014 03:33 PM, Andrew Morton wrote: > >>> On Wed, 18 Dec 2013 08:42:49 +0800 Bob Liu wrote: > >>> > >>>>> This BUG_ON() was triggered when called from try_to_unmap_cluster() > >>>>> which didn't lock the page. > >>>>> And it's safe to mlock_vma_page() without PageLocked, so this patch > >>>>> fix this issue by removing that BUG_ON() simply. > >>>>> > >>> This patch doesn't appear to be going anywhere, so I will drop it. > >>> Please let's check to see whether the bug still exists and if so, > >>> start another round of bugfixing. > >> > >> This bug still happens on the latest -next kernel. > > > > Yeah, I recognized it. I'm preparing new patch. Thanks. > > What will be your approach? After we had the discussion some month ago > about m(un)lock vs migration I've concluded that there is no race that > page lock helps, and removing the BUG_ON() would be indeed correct. Just > needs to be correctly explained and documentation updated as well. This is not just a -next problem btw, I just hit this in 3.14-rc6 Dave -- 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