From patchwork Thu Aug 20 09:18:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 265862 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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 3231AC433DF for ; Thu, 20 Aug 2020 09:27:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0485C22CF6 for ; Thu, 20 Aug 2020 09:27:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597915673; bh=7INpsne5XqqcM9dgEgvMScCRO9DTUSEYmf2NWPPV3P4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0GHqdbKIo/WbQfhT/k+hzAaTKbhbWjEPmS79nhnqgk9ts13oKhNyabY5UPT6fh8mZ zBjHy2fKWMwmdm1xRETLD8PQCKMW6Z3y3CrCbb4HZF+acrqSZsgT5spc/EQE3PpT7a b+dxHqjbvMaDTvghDkBr+5Q4YRvK1oqMtLEHqlm0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726980AbgHTJ1t (ORCPT ); Thu, 20 Aug 2020 05:27:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:33620 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727949AbgHTJ1A (ORCPT ); Thu, 20 Aug 2020 05:27:00 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B759122D08; Thu, 20 Aug 2020 09:26:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597915618; bh=7INpsne5XqqcM9dgEgvMScCRO9DTUSEYmf2NWPPV3P4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HY3fnobaP9xShBvvdAxyVoP5IYHKfjG6dwndLcQByu1mQq6zrzwPSqswB30lxJJ4f prFvRv+kY0xuqVmmXOXWh0I9KcjWbFuDZJEp6Pa1k0FTt7k8ktC2kUdw2cyxOwMaUt 9aZ3Ua3wnBb4FN8lpXN3lt8K6wGGi1+X6rV5fFpk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hugh Dickins , Andrew Morton , "Kirill A. Shutemov" , Andrea Arcangeli , Mike Kravetz , Song Liu , Linus Torvalds Subject: [PATCH 5.8 077/232] khugepaged: collapse_pte_mapped_thp() flush the right range Date: Thu, 20 Aug 2020 11:18:48 +0200 Message-Id: <20200820091616.540850550@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091612.692383444@linuxfoundation.org> References: <20200820091612.692383444@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Hugh Dickins commit 723a80dafed5c95889d48baab9aa433a6ffa0b4e upstream. pmdp_collapse_flush() should be given the start address at which the huge page is mapped, haddr: it was given addr, which at that point has been used as a local variable, incremented to the end address of the extent. Found by source inspection while chasing a hugepage locking bug, which I then could not explain by this. At first I thought this was very bad; then saw that all of the page translations that were not flushed would actually still point to the right pages afterwards, so harmless; then realized that I know nothing of how different architectures and models cache intermediate paging structures, so maybe it matters after all - particularly since the page table concerned is immediately freed. Much easier to fix than to think about. Fixes: 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP") Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Acked-by: Kirill A. Shutemov Cc: Andrea Arcangeli Cc: Mike Kravetz Cc: Song Liu Cc: [5.4+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021204390.27773@eggly.anvils Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/khugepaged.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1502,7 +1502,7 @@ void collapse_pte_mapped_thp(struct mm_s /* step 4: collapse pmd */ ptl = pmd_lock(vma->vm_mm, pmd); - _pmd = pmdp_collapse_flush(vma, addr, pmd); + _pmd = pmdp_collapse_flush(vma, haddr, pmd); spin_unlock(ptl); mm_dec_nr_ptes(mm); pte_free(mm, pmd_pgtable(_pmd));