From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AB64C3A5A6 for ; Thu, 19 Sep 2019 16:42:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E6A1620882 for ; Thu, 19 Sep 2019 16:42:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732777AbfISQmM (ORCPT ); Thu, 19 Sep 2019 12:42:12 -0400 Received: from foss.arm.com ([217.140.110.172]:33950 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732225AbfISQmL (ORCPT ); Thu, 19 Sep 2019 12:42:11 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2FF0B28; Thu, 19 Sep 2019 09:42:11 -0700 (PDT) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9A4983F575; Thu, 19 Sep 2019 09:42:08 -0700 (PDT) Date: Thu, 19 Sep 2019 17:42:06 +0100 From: Catalin Marinas To: Jia He Cc: Will Deacon , Mark Rutland , James Morse , Marc Zyngier , Matthew Wilcox , "Kirill A. Shutemov" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Suzuki Poulose , Punit Agrawal , Anshuman Khandual , Alex Van Brunt , Robin Murphy , Thomas Gleixner , Andrew Morton , =?iso-8859-1?B?Suly9G1l?= Glisse , Ralph Campbell , hejianet@gmail.com, Kaly Xin Subject: Re: [PATCH v5 3/3] mm: fix double page fault on arm64 if PTE_AF is cleared Message-ID: <20190919164206.GE6472@arrakis.emea.arm.com> References: <20190919161204.142796-1-justin.he@arm.com> <20190919161204.142796-4-justin.he@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190919161204.142796-4-justin.he@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 20, 2019 at 12:12:04AM +0800, Jia He wrote: > @@ -2152,7 +2163,29 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo > */ > if (unlikely(!src)) { > void *kaddr = kmap_atomic(dst); > - void __user *uaddr = (void __user *)(va & PAGE_MASK); > + void __user *uaddr = (void __user *)(addr & PAGE_MASK); > + pte_t entry; > + > + /* On architectures with software "accessed" bits, we would > + * take a double page fault, so mark it accessed here. > + */ > + if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) { > + spin_lock(vmf->ptl); > + if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { > + entry = pte_mkyoung(vmf->orig_pte); > + if (ptep_set_access_flags(vma, addr, > + vmf->pte, entry, 0)) > + update_mmu_cache(vma, addr, vmf->pte); > + } else { > + /* Other thread has already handled the fault > + * and we don't need to do anything. If it's > + * not the case, the fault will be triggered > + * again on the same address. > + */ > + return -1; > + } > + spin_unlock(vmf->ptl); Returning with the spinlock held doesn't normally go very well ;). -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47AD3C3A5A6 for ; Thu, 19 Sep 2019 16:42:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2AA2D20882 for ; Thu, 19 Sep 2019 16:42:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="f0RSFIAt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2AA2D20882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ewgYJg8skm4n7RV2v7XRaKAb8lk5QmONAe0bpI/17o8=; b=f0RSFIAtp9U2Cg yy+IQoggQ/ymlk0YeELC6wGNVS7IGftI3vogNSICawr71EYzPdlG/16hbh0LzCXwCcq6sCpi/T/+V ivyIZpaQerE0ioMHYiR8cQYSDSTVbPNgLYD/37snPZe4cMuUc+u66trWMKap2MueqioUlyjXLokXC b5KJ6ZApR+qQwdLPziZMK4Aq8RNvuOHbtfaG7yWycDMv8vlrqhlmSQnLVNV9KAj2dsCjkMV0qgfU0 A+pFBvcqGCRarKc5TTiso1eMQJzhnvR+3+7ghW+qJhm9M9ycdPZ9PfX+hOz1fU7J/yS2vdikzUwOK ZWP3PiTmLl/f7bxXF6dg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAzVZ-0002P5-No; Thu, 19 Sep 2019 16:42:17 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iAzVU-0002OH-91 for linux-arm-kernel@lists.infradead.org; Thu, 19 Sep 2019 16:42:14 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2FF0B28; Thu, 19 Sep 2019 09:42:11 -0700 (PDT) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9A4983F575; Thu, 19 Sep 2019 09:42:08 -0700 (PDT) Date: Thu, 19 Sep 2019 17:42:06 +0100 From: Catalin Marinas To: Jia He Subject: Re: [PATCH v5 3/3] mm: fix double page fault on arm64 if PTE_AF is cleared Message-ID: <20190919164206.GE6472@arrakis.emea.arm.com> References: <20190919161204.142796-1-justin.he@arm.com> <20190919161204.142796-4-justin.he@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190919161204.142796-4-justin.he@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190919_094212_652625_123F6FE0 X-CRM114-Status: GOOD ( 14.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Kaly Xin , Ralph Campbell , Andrew Morton , Suzuki Poulose , Marc Zyngier , Anshuman Khandual , linux-kernel@vger.kernel.org, Matthew Wilcox , linux-mm@kvack.org, =?iso-8859-1?B?Suly9G1l?= Glisse , James Morse , linux-arm-kernel@lists.infradead.org, Punit Agrawal , hejianet@gmail.com, Thomas Gleixner , Will Deacon , Alex Van Brunt , "Kirill A. Shutemov" , Robin Murphy Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 20, 2019 at 12:12:04AM +0800, Jia He wrote: > @@ -2152,7 +2163,29 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo > */ > if (unlikely(!src)) { > void *kaddr = kmap_atomic(dst); > - void __user *uaddr = (void __user *)(va & PAGE_MASK); > + void __user *uaddr = (void __user *)(addr & PAGE_MASK); > + pte_t entry; > + > + /* On architectures with software "accessed" bits, we would > + * take a double page fault, so mark it accessed here. > + */ > + if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) { > + spin_lock(vmf->ptl); > + if (likely(pte_same(*vmf->pte, vmf->orig_pte))) { > + entry = pte_mkyoung(vmf->orig_pte); > + if (ptep_set_access_flags(vma, addr, > + vmf->pte, entry, 0)) > + update_mmu_cache(vma, addr, vmf->pte); > + } else { > + /* Other thread has already handled the fault > + * and we don't need to do anything. If it's > + * not the case, the fault will be triggered > + * again on the same address. > + */ > + return -1; > + } > + spin_unlock(vmf->ptl); Returning with the spinlock held doesn't normally go very well ;). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel