From patchwork Thu Apr 28 15:42:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 567759 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52D82C4332F for ; Thu, 28 Apr 2022 15:43:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349529AbiD1Pq2 (ORCPT ); Thu, 28 Apr 2022 11:46:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349506AbiD1PqU (ORCPT ); Thu, 28 Apr 2022 11:46:20 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37B9EB715C; Thu, 28 Apr 2022 08:43:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AB08EB82DAA; Thu, 28 Apr 2022 15:42:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D529FC385AF; Thu, 28 Apr 2022 15:42:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651160578; bh=cUTeQdSbuKp1C1IB6s6cp2R4rK9jLAPr9VFjKwq5OVg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NVbN9lEcnOc/+Jxc3KuGDhg6Dr8dnI5JqV5nzay/g7SJqVoLqShtoT6oewTEOLYwD flLEKLx58kSL9hiOdWdGzg23ZYE1TfoW1gPGUCsbpTcgy2HWR66hQLfLqNuQoFf7my sW0RXQzWXELykHKHBoXm5bo5DKucM8/ujbgHuW0s= From: Greg Kroah-Hartman To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Muchun Song , Axel Rasmussen , David Rientjes , Fam Zheng , "Kirill A . Shutemov" , Lars Persson , Mike Kravetz , Peter Xu , Xiongchun Duan , Zi Yan , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman Subject: [PATCH AUTOSEL 06/14] mm: userfaultfd: fix missing cache flush in mcopy_atomic_pte() and __mcopy_atomic() Date: Thu, 28 Apr 2022 17:42:14 +0200 Message-Id: <20220428154222.1230793-6-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220428154222.1230793-1-gregkh@linuxfoundation.org> References: <20220428154222.1230793-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1990; i=gregkh@linuxfoundation.org; h=from:subject; bh=w/4yshSSx6bYlycE+CXvFti1EqgLl8fqTCv8PDJp7+o=; b=owGbwMvMwCRo6H6F97bub03G02pJDElZW+8emM35cFrCfpYrsaulchb4ctgd5eWKLZG7/95q8YWr nNd3dcSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBErtQyLJh7/oDIuZBg9RvHvypanU rzKWsu+8swP+T74rvTtdWWGBqf3uH1JJPj3tWP0gA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Muchun Song commit 7c25a0b89a487878b0691e6524fb5a8827322194 upstream. userfaultfd calls mcopy_atomic_pte() and __mcopy_atomic() which do not do any cache flushing for the target page. Then the target page will be mapped to the user space with a different address (user address), which might have an alias issue with the kernel address used to copy the data from the user to. Fix this by insert flush_dcache_page() after copy_from_user() succeeds. Link: https://lkml.kernel.org/r/20220210123058.79206-7-songmuchun@bytedance.com Fixes: b6ebaedb4cb1 ("userfaultfd: avoid mmap_sem read recursion in mcopy_atomic") Fixes: c1a4de99fada ("userfaultfd: mcopy_atomic|mfill_zeropage: UFFDIO_COPY|UFFDIO_ZEROPAGE preparation") Signed-off-by: Muchun Song Cc: Axel Rasmussen Cc: David Rientjes Cc: Fam Zheng Cc: Kirill A. Shutemov Cc: Lars Persson Cc: Mike Kravetz Cc: Peter Xu Cc: Xiongchun Duan Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/userfaultfd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 885e5adb0168..7259f96faaa0 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -153,6 +153,8 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm, /* don't free the page */ goto out; } + + flush_dcache_page(page); } else { page = *pagep; *pagep = NULL; @@ -628,6 +630,7 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, err = -EFAULT; goto out; } + flush_dcache_page(page); goto retry; } else BUG_ON(page);