Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755585AbaDGTlH (ORCPT ); Mon, 7 Apr 2014 15:41:07 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:46243 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754687AbaDGTlF (ORCPT ); Mon, 7 Apr 2014 15:41:05 -0400 Message-ID: <5342FF3E.6030306@oracle.com> Date: Mon, 07 Apr 2014 15:40:46 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: "Kirill A. Shutemov" , Hugh Dickins CC: "Kirill A. Shutemov" , Andrew Morton , David Rientjes , Andrea Arcangeli , "H. Peter Anvin" , Mel Gorman , Dave Jones , linux-mm , "linux-kernel@vger.kernel.org" Subject: Re: mm: BUG in do_huge_pmd_wp_page References: <51559150.3040407@oracle.com> <515D882E.6040001@oracle.com> <533F09F0.1050206@oracle.com> <20140407144835.GA17774@node.dhcp.inet.fi> In-Reply-To: <20140407144835.GA17774@node.dhcp.inet.fi> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It also breaks fairly quickly under testing because: On 04/07/2014 10:48 AM, Kirill A. Shutemov wrote: > + if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC)) { > + spin_lock(ptl); ^ We go into atomic > + if (unlikely(!pmd_same(*pmd, orig_pmd))) > + goto out_race; > + } > + > if (!page) > clear_huge_page(new_page, haddr, HPAGE_PMD_NR); > else > copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); copy_user_huge_page() doesn't like running in atomic state, and asserts might_sleep(). Thanks, Sasha -- 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/