From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com [209.85.212.179]) by kanga.kvack.org (Postfix) with ESMTP id 646B26B0031 for ; Wed, 12 Feb 2014 07:03:50 -0500 (EST) Received: by mail-wi0-f179.google.com with SMTP id hn9so6759264wib.0 for ; Wed, 12 Feb 2014 04:03:49 -0800 (PST) Received: from www62.your-server.de (www62.your-server.de. [213.133.104.62]) by mx.google.com with ESMTPS id x43si38392068eey.229.2014.02.12.04.03.47 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 12 Feb 2014 04:03:48 -0800 (PST) Message-ID: <52FB62EE.7070205@iogearbox.net> Date: Wed, 12 Feb 2014 13:02:54 +0100 From: Daniel Borkmann MIME-Version: 1.0 Subject: Re: [BUG] at include/linux/page-flags.h:415 (PageTransHuge) References: <52D03A9E.2030309@iogearbox.net> <20140110222248.4e8419ca.akpm@linux-foundation.org> <52D147F1.3040803@iogearbox.net> <52D3BCE9.4020405@suse.cz> <52D3D060.1010301@iogearbox.net> <52D69AB4.6000309@suse.cz> <52D6B213.4020602@iogearbox.net> <52EBB5E6.8010007@suse.cz> <20140207185816.GA7764@order.stressinduktion.org> In-Reply-To: <20140207185816.GA7764@order.stressinduktion.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , Andrew Morton , linux-kernel , Michel Lespinasse , linux-mm , Jared Hulbert , netdev , Thomas Hellstrom , John David Anglin , HATAYAMA Daisuke , Konstantin Khlebnikov , Carsten Otte , Peter Zijlstra Hi Vlastimil, On 02/07/2014 07:58 PM, Hannes Frederic Sowa wrote: > On Fri, Jan 31, 2014 at 03:40:38PM +0100, Vlastimil Babka wrote: >> From: Vlastimil Babka >> Date: Fri, 31 Jan 2014 11:50:21 +0100 >> Subject: [PATCH] mm: include VM_MIXEDMAP flag in the VM_SPECIAL list to avoid >> m(un)locking >> >> Daniel Borkmann reported a bug with VM_BUG_ON assertions failing where >> munlock_vma_pages_range() thinks it's unexpectedly in the middle of a THP page. >> This can be reproduced in tools/testing/selftests/net/ by running make and >> then ./psock_tpacket. >> >> The problem is that an order=2 compound page (allocated by >> alloc_one_pg_vec_page() is part of the munlocked VM_MIXEDMAP vma (mapped by >> packet_mmap()) and mistaken for a THP page and assumed to be order=9. >> >> The checks for THP in munlock came with commit ff6a6da60b89 ("mm: accelerate >> munlock() treatment of THP pages"), i.e. since 3.9, but did not trigger a bug. >> It just makes munlock_vma_pages_range() skip such compound pages until the next >> 512-pages-aligned page, when it encounters a head page. This is however not a >> problem for vma's where mlocking has no effect anyway, but it can distort the >> accounting. >> Since commit 7225522bb ("mm: munlock: batch non-THP page isolation and >> munlock+putback using pagevec") this can trigger a VM_BUG_ON in PageTransHuge() >> check. >> >> This patch fixes the issue by adding VM_MIXEDMAP flag to VM_SPECIAL - a list of >> flags that make vma's non-mlockable and non-mergeable. The reasoning is that >> VM_MIXEDMAP vma's are similar to VM_PFNMAP, which is already on the VM_SPECIAL >> list, and both are intended for non-LRU pages where mlocking makes no sense >> anyway. Thanks a lot for your efforts. Is your patch queued up somewhere for mainline and stable? > I also ran into this problem and wanted to ask what the status of this > patch is? Does it need further testing? I can surely help with that. ;) > > Thanks, > > Hannes > -- 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