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=-10.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 C6563C49ED7 for ; Fri, 20 Sep 2019 14:21:25 +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 9774A207E0 for ; Fri, 20 Sep 2019 14:21:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Ig7tnDIa"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="yLfvnX9x" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9774A207E0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=shutemov.name 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=oXNuJT5Ko6aZIkOJbncb5lx/5m8AzC0WbzCVAWdBRoo=; b=Ig7tnDIaS8xmXb Ja9gjnd5sJIjxdTzvl3bKUuD463bnNNNHtjZQbbaO0nkBY1sm1IUCUvKAn6+S15bEbTCW4UxYylNq glwbCKeyAP5QJXpmQlgdLMRNBK0V6mpD4SzTVZwHpB8/JNVQbSTZmcROTFUgZob091bNqfb07GAUw u8sbC56JOEC4WdbdsN5r8auQQvh0MGGKq34aBz60duMz2FrYmdxy3DXaPocbdkAklvwcqzSZ+qaga t2T+w+Kkb105xMKyq5byMfoZWZdeMGgjXOvXYQihUmSTvFwbmBDksmTwSFf8imblQHDG74mrvtKvW 8DMv1jF4CNMou0vTrv5w==; 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 1iBJmg-0002O3-Bj; Fri, 20 Sep 2019 14:21:18 +0000 Received: from mail-ed1-x541.google.com ([2a00:1450:4864:20::541]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iBJmd-0002NA-Mr for linux-arm-kernel@lists.infradead.org; Fri, 20 Sep 2019 14:21:17 +0000 Received: by mail-ed1-x541.google.com with SMTP id t3so6554320edw.13 for ; Fri, 20 Sep 2019 07:21:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=BsObysdauMqFxQskSLuaANmrbU7y5OuxMxy3HbJkoH8=; b=yLfvnX9xGqCtoBtlknnpzBw2B3alTmNk3CXvDaf3MoBnN9PZaUdqLKOkT9Zzh/n2OZ SbD1/4Gj6cP3aQ3iwHLpmUQ2nYoif61BK45NZZpQ4xgYet8vCIJtZZ0g2qNLLsC7NQ8Z DjkOXKCNXhfgfNkhIvAiJmmSTB3991s02/L1RlMXWEpQWTyCZBRv0OCy9MJOENQS/bav 6t/uTMbrBaUhwoSZkv76hO5m1yScZU92EeaOPA4UzOax8JCzIFw23PfzQl3JBdx6KdyI hsQ4SUOsTdBkoEC4cbFw3wKzPEQvIhKU7o5rgqrJlGmwI5fBkqR0xZ8bMGc+EnyV6y67 ZWPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=BsObysdauMqFxQskSLuaANmrbU7y5OuxMxy3HbJkoH8=; b=sJ/x3sV+6c6Ts92ItkYlqBjAcncgsiVu6K4a5996ELQtFvsf6mvVlW8y1xk05782Jj jcTYRWt3cL38SE+Mp8+kFbWfirPVoek/zu1QGt0dOHNVb1I23yl/6/mzMwUiYxOUCC/U Itc7JKKs+n6WGaHjznOeK2adBvXFxShPq3j2HvSjtFY10B2enUVGXwVyp67KuHqHnSjJ ehntVpRoxpZTVfrtYu7M3gxD97kPl3Mh7hgRd7y3nVR2imj3/WM8+rJqT8oW+y5Hl2ZN MB7vYpFuFEqnIsdRVD/vbsaxPb1O6OWqBmJuAJo/diHyShz4wlI0idr6wMas87xfBreu l/Ew== X-Gm-Message-State: APjAAAVSnZsdoO2mBsInypvvHlnQ+9Fokl5JEy+GhF3sPFWhXrMqj+un i9XLn974ERKLK4xwndDd1BJVkw== X-Google-Smtp-Source: APXvYqynqm5TTKBimN51b6OZzEkRrwe+U7oN1i3ygL0xADjoA6jCeUaZdJrdhbRfLIjJwN06Jc3i/Q== X-Received: by 2002:a17:906:6d95:: with SMTP id h21mr19767726ejt.192.1568989273886; Fri, 20 Sep 2019 07:21:13 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id g15sm352149edp.0.2019.09.20.07.21.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Sep 2019 07:21:13 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id 6733D101405; Fri, 20 Sep 2019 17:21:13 +0300 (+03) Date: Fri, 20 Sep 2019 17:21:13 +0300 From: "Kirill A. Shutemov" To: Jia He Subject: Re: [PATCH v7 3/3] mm: fix double page fault on arm64 if PTE_AF is cleared Message-ID: <20190920142113.52mdiflo4yghlsmu@box> References: <20190920135437.25622-1-justin.he@arm.com> <20190920135437.25622-4-justin.he@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190920135437.25622-4-justin.he@arm.com> User-Agent: NeoMutt/20180716 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190920_072115_752000_58C53FE6 X-CRM114-Status: GOOD ( 14.45 ) 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 , Catalin Marinas , linux-mm@kvack.org, Punit Agrawal , Will Deacon , Alex Van Brunt , Marc Zyngier , Anshuman Khandual , Matthew Wilcox , Kaly Xin , hejianet@gmail.com, Ralph Campbell , Suzuki Poulose , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Thomas Gleixner , nd@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, James Morse , Andrew Morton , Robin Murphy , "Kirill A. Shutemov" 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 09:54:37PM +0800, Jia He wrote: > When we tested pmdk unit test [1] vmmalloc_fork TEST1 in arm64 guest, there > will be a double page fault in __copy_from_user_inatomic of cow_user_page. > > Below call trace is from arm64 do_page_fault for debugging purpose > [ 110.016195] Call trace: > [ 110.016826] do_page_fault+0x5a4/0x690 > [ 110.017812] do_mem_abort+0x50/0xb0 > [ 110.018726] el1_da+0x20/0xc4 > [ 110.019492] __arch_copy_from_user+0x180/0x280 > [ 110.020646] do_wp_page+0xb0/0x860 > [ 110.021517] __handle_mm_fault+0x994/0x1338 > [ 110.022606] handle_mm_fault+0xe8/0x180 > [ 110.023584] do_page_fault+0x240/0x690 > [ 110.024535] do_mem_abort+0x50/0xb0 > [ 110.025423] el0_da+0x20/0x24 > > The pte info before __copy_from_user_inatomic is (PTE_AF is cleared): > [ffff9b007000] pgd=000000023d4f8003, pud=000000023da9b003, pmd=000000023d4b3003, pte=360000298607bd3 > > As told by Catalin: "On arm64 without hardware Access Flag, copying from > user will fail because the pte is old and cannot be marked young. So we > always end up with zeroed page after fork() + CoW for pfn mappings. we > don't always have a hardware-managed access flag on arm64." > > This patch fix it by calling pte_mkyoung. Also, the parameter is > changed because vmf should be passed to cow_user_page() > > Add a WARN_ON_ONCE when __copy_from_user_inatomic() returns error > in case there can be some obscure use-case.(by Kirill) > > [1] https://github.com/pmem/pmdk/tree/master/src/test/vmmalloc_fork > > Reported-by: Yibo Cai > Signed-off-by: Jia He Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel