From patchwork Tue May 10 03:45:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baolin Wang X-Patchwork-Id: 12844506 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5595FC433FE for ; Tue, 10 May 2022 03:48:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date:Subject:Cc:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=eLFvVdsL7VoO2pg+zIgo1UcoQxmpGOtCldPZKuuCF5A=; b=MMhRUSIa1V+5bU klLTNQU9IukrE+PewtyTNM4hQfq1pv0VWQtLUG2JjX5EQcBC0kEdB9gXWmGVTPEcnikRGNanb5P7H 8/mnkjSdodgsSFUt99oxACf3jJp+5ImNY2SPY8f1A6iejRz/3Z1474AzCJ4A+IfA6zSCDZcjyPadp /DxdmtwDR6o+3u/Et6Xw6z57uJ6IIqWgvPdy9gLryEYoA7GXufAXDT+1KcXT2gdrCdUenGs9A4c7u inlqpZvGdM69F+3aYxsgINthENDyvhAnTc25QMSdSC3boKveFbw7DN6smjj0TAesneTtY33yLTKlC CPD+V37ogw93H5xk1P7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1noGpX-00HOAj-Da; Tue, 10 May 2022 03:46:35 +0000 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1noGpT-00HO8B-NE for linux-arm-kernel@lists.infradead.org; Tue, 10 May 2022 03:46:34 +0000 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R161e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04400; MF=baolin.wang@linux.alibaba.com; NM=1; PH=DS; RN=32; SR=0; TI=SMTPD_---0VCohuDm_1652154383; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VCohuDm_1652154383) by smtp.aliyun-inc.com(127.0.0.1); Tue, 10 May 2022 11:46:24 +0800 From: Baolin Wang To: akpm@linux-foundation.org, mike.kravetz@oracle.com, catalin.marinas@arm.com, will@kernel.org Cc: songmuchun@bytedance.com, tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com, deller@gmx.de, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, arnd@arndb.de, baolin.wang@linux.alibaba.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v3 0/3] Fix CONT-PTE/PMD size hugetlb issue when unmapping or migrating Date: Tue, 10 May 2022 11:45:57 +0800 Message-Id: X-Mailer: git-send-email 1.8.3.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220509_204631_945901_7C8778C4 X-CRM114-Status: GOOD ( 12.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, Now migrating a hugetlb page or unmapping a poisoned hugetlb page, we'll use ptep_clear_flush() and set_pte_at() to nuke the page table entry and remap it, and this is incorrect for CONT-PTE or CONT-PMD size hugetlb page, which will cause potential data consistent issue. This patch set will change to use hugetlb related APIs to fix this issue, please find details in each patch. Thanks. Note: Mike pointed out the huge_ptep_get() will only return the one specific value, and it would not take into account the dirty or young bits of CONT-PTE/PMDs like the huge_ptep_get_and_clear() [1]. This inconsistent issue is not introduced by this patch set, and will address this issue in another thread [2]. Meanwhile the uffd for hugetlb case [3] pointed by Gerald also need another patch to address. [1] https://lore.kernel.org/linux-mm/85bd80b4-b4fd-0d3f-a2e5-149559f2f387@oracle.com/ [2] https://lore.kernel.org/all/cover.1651998586.git.baolin.wang@linux.alibaba.com/ [3] https://lore.kernel.org/linux-mm/20220503120343.6264e126@thinkpad/ Changes from v2: - Collect reviewed tags from Muchun and Mike. - Drop the unnecessary casting in hugetlb.c. - Fix building errors with adding dummy functions for !CONFIG_HUGETLB_PAGE. Changes from v1: - Add acked tag from Mike. - Update some commit message. - Add VM_BUG_ON in try_to_unmap() for hugetlb case. - Add an explict void casting for huge_ptep_clear_flush() in hugetlb.c. Baolin Wang (3): mm: change huge_ptep_clear_flush() to return the original pte mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when migration mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when unmapping arch/arm64/include/asm/hugetlb.h | 4 +-- arch/arm64/mm/hugetlbpage.c | 12 +++----- arch/ia64/include/asm/hugetlb.h | 4 +-- arch/mips/include/asm/hugetlb.h | 9 ++++-- arch/parisc/include/asm/hugetlb.h | 4 +-- arch/powerpc/include/asm/hugetlb.h | 9 ++++-- arch/s390/include/asm/hugetlb.h | 6 ++-- arch/sh/include/asm/hugetlb.h | 4 +-- arch/sparc/include/asm/hugetlb.h | 4 +-- include/asm-generic/hugetlb.h | 4 +-- include/linux/hugetlb.h | 11 +++++++ mm/rmap.c | 63 ++++++++++++++++++++++++-------------- 12 files changed, 83 insertions(+), 51 deletions(-)