From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f44.google.com (mail-yh0-f44.google.com [209.85.213.44]) by kanga.kvack.org (Postfix) with ESMTP id 89B796B0035 for ; Mon, 16 Dec 2013 19:18:49 -0500 (EST) Received: by mail-yh0-f44.google.com with SMTP id f64so4395074yha.3 for ; Mon, 16 Dec 2013 16:18:49 -0800 (PST) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id l5si14016644yhl.199.2013.12.16.16.18.48 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 16 Dec 2013 16:18:48 -0800 (PST) Message-ID: <52AF9860.9000303@oracle.com> Date: Mon, 16 Dec 2013 19:18:40 -0500 From: Sasha Levin MIME-Version: 1.0 Subject: Re: [patch 019/154] mm: make madvise(MADV_WILLNEED) support swap file prefetch References: <20130223003232.4CDDB5A41B6@corp2gmr1-2.hot.corp.google.com> <52AA0613.2000908@oracle.com> <52AE271C.4040805@oracle.com> <20131216124754.29063E0090@blue.fi.intel.com> <52AF19CF.2060102@oracle.com> <20131216205244.GG21218@redhat.com> In-Reply-To: <20131216205244.GG21218@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: "Kirill A. Shutemov" , Linus Torvalds , Andrew Morton , shli@kernel.org, Hugh Dickins , Rik van Riel , Shaohua Li , linux-mm Hi Andrea, On 12/16/2013 03:52 PM, Andrea Arcangeli wrote: > Is the bug reproducible? If yes the simplest is probably to add some > allocation tracking to the page, so if page->ptl is null we can simply > print a stack trace of who allocated the page (and later forgot to > initialize the ptl). Yes, it's easy to reproduce. I've done as suggested and here's the trace from the allocation: [ 184.139519] [] save_stack_trace+0x2f/0x50 [ 184.140706] [] get_page_from_freelist+0x759/0x7a0 [ 184.141605] [] __alloc_pages_nodemask+0x3b8/0x520 [ 184.142810] [] alloc_pages_vma+0x1df/0x220 [ 184.143631] [] do_huge_pmd_wp_page+0x2d8/0x730 [ 184.144526] [] __handle_mm_fault+0x2b1/0x3d0 [ 184.145361] [] handle_mm_fault+0x133/0x1c0 [ 184.146129] [] __get_user_pages+0x448/0x640 [ 184.147055] [] __mlock_vma_pages_range+0xd4/0xe0 [ 184.147980] [] __mm_populate+0x110/0x190 [ 184.148933] [] SyS_mlock+0xf2/0x130 [ 184.149689] [] tracesys+0xdd/0xe2 > Agree with Kirill that it would help to verify the bug goes away by > disabling USE_SPLIT_PTE_PTLOCKS. It seems that the bug is gone without USE_SPLIT_PTE_PTLOCKS. Thanks, Sasha -- 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