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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C56F5C433EF for ; Fri, 13 May 2022 14:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381419AbiEMOgE (ORCPT ); Fri, 13 May 2022 10:36:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381030AbiEMOdY (ORCPT ); Fri, 13 May 2022 10:33:24 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AB745E748; Fri, 13 May 2022 07:29:34 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 041F062159; Fri, 13 May 2022 14:29:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 407DFC34100; Fri, 13 May 2022 14:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652452173; bh=ovDcXZKFP6/Q28vqbQAc3j9wHd64tfumZlesJ/Lzcus=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NhS70CLOuphqKfjiJqEfalIZ50r0UnMmgT0YwPG7FVFEeqTA9XRQwVslj8bKcA0bo 1n8lGR0u5jQ+EVaY6g5ciRHSOddfiDS7/PrQGaHA1DewxmU7hEctCtb4JTSPZSZyZJ F66FFqGIJegkv2nO7c8qazWjrS37OhnzEr/Lttak= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Muchun Song , Mike Kravetz , Axel Rasmussen , David Rientjes , Fam Zheng , "Kirill A. Shutemov" , Lars Persson , Peter Xu , Xiongchun Duan , Zi Yan , Andrew Morton , Linus Torvalds Subject: [PATCH 5.17 07/12] mm: shmem: fix missing cache flush in shmem_mfill_atomic_pte() Date: Fri, 13 May 2022 16:24:07 +0200 Message-Id: <20220513142228.870480590@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142228.651822943@linuxfoundation.org> References: <20220513142228.651822943@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Muchun Song commit 19b482c29b6f3805f1d8e93015847b89e2f7f3b1 upstream. userfaultfd calls shmem_mfill_atomic_pte() which does 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. Insert flush_dcache_page() in non-zero-page case. And replace clear_highpage() with clear_user_highpage() which already considers the cache maintenance. Link: https://lkml.kernel.org/r/20220210123058.79206-6-songmuchun@bytedance.com Fixes: 8d1039634206 ("userfaultfd: shmem: add shmem_mfill_zeropage_pte for userfaultfd support") Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Signed-off-by: Muchun Song Reviewed-by: Mike Kravetz Cc: Axel Rasmussen Cc: David Rientjes Cc: Fam Zheng Cc: Kirill A. Shutemov Cc: Lars Persson 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/shmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2357,8 +2357,10 @@ int shmem_mfill_atomic_pte(struct mm_str /* don't free the page */ goto out_unacct_blocks; } + + flush_dcache_page(page); } else { /* ZEROPAGE */ - clear_highpage(page); + clear_user_highpage(page, dst_addr); } } else { page = *pagep;