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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD3D6C433EF for ; Wed, 16 Feb 2022 06:16:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id ED04F6B0078; Wed, 16 Feb 2022 01:16:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E7EB96B007B; Wed, 16 Feb 2022 01:16:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D473D6B007D; Wed, 16 Feb 2022 01:16:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0109.hostedemail.com [216.40.44.109]) by kanga.kvack.org (Postfix) with ESMTP id C2CE06B0078 for ; Wed, 16 Feb 2022 01:16:52 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 7D3DD4F32F6 for ; Wed, 16 Feb 2022 06:16:52 +0000 (UTC) X-FDA: 79147634664.23.4B818B3 Received: from mail-yb1-f178.google.com (mail-yb1-f178.google.com [209.85.219.178]) by imf06.hostedemail.com (Postfix) with ESMTP id 70B5A180004 for ; Wed, 16 Feb 2022 06:16:51 +0000 (UTC) Received: by mail-yb1-f178.google.com with SMTP id v63so2916936ybv.10 for ; Tue, 15 Feb 2022 22:16:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=fj0gD7ulTBZq25O5ipO8sbzaZnByNFYzTOaIrem2GJI=; b=v/JgsETLxe0/hm/AA5GsACF8WbkW5lYlBICmSCPBJRwkdphqlFcGSU4zn7Uia3n8l8 ChzEAUcPZ8tPWX133x+zQZ8B+u5NtXXDbp7FYSXcEv7HM5SI2nn3hfgt3lVy6mXrYbwB 8RvU1KZw+re5hvp27VM8b4Sp8KuYugX2l3Eqg9B3Oc5fd8+SjF7zzRi51zscms/4Ap+O crduJSOlnNUMP1ARucXq1AXRo3bF1P4ntDGqJW6JqO11TK/+ldRM31w5a5NLQQDcVyTE LhLIHUUFBR/J/s7Uk7MF3Bf1nGumQ+tDNUD7qv/oMVJ/PP/uz0quLcmV9DRfKouQxVhq /XQg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fj0gD7ulTBZq25O5ipO8sbzaZnByNFYzTOaIrem2GJI=; b=lhuqHfOPLuTucoQrtPfDyttinHDnIFmdF/lHUUNUAYHGlWQ/ox+nZHjot05m2xe7zp QxjM7kjx1Mx4Jt21zh3CArszfn8uQ3KfqvuS/O02/Kz+erIIMwfx/lfutZd8x9kIaQKc pmES1OISW4ab5WOi+3F6y+SYpkz3c3MfDxqdrbuOTfloE2otgBJcHE1AcaV4GJ/m2dHY jc9dgiLq0DET/0nUEOCPEeHcdg2jXC7+utC0sEjwWhd2XIDToUg/SAikm3sKkaEn5at3 wwEkkigU6gJ+ArRzRSQjpC8epoP2TPdpN6QmXh0vrrK6eh5uhM9FaGeWB7QU5un4tEXL yUWQ== X-Gm-Message-State: AOAM532euRR0xK6XFR4hF2RYYWsON1ZhQ/hCqVkJWiHeraTbJNJLhaSV KXKQ/PAxNWPCml73XuinkjmL/M+2eDBrk8MfGzaD3g== X-Google-Smtp-Source: ABdhPJzX2bajWAwxTro869+zweYxCrKF4uoJ8QpyUAt4H2OSUROm/o52wbTCM4bT6j0jOd2XreydTzdDFgOhQz8gl1w= X-Received: by 2002:a25:d145:0:b0:611:c6ef:7c0d with SMTP id i66-20020a25d145000000b00611c6ef7c0dmr830341ybg.703.1644992210451; Tue, 15 Feb 2022 22:16:50 -0800 (PST) MIME-Version: 1.0 References: <20220210123058.79206-1-songmuchun@bytedance.com> <20220210123058.79206-6-songmuchun@bytedance.com> <39ab53c4-cb2f-82f4-1097-65d000284b23@oracle.com> In-Reply-To: <39ab53c4-cb2f-82f4-1097-65d000284b23@oracle.com> From: Muchun Song Date: Wed, 16 Feb 2022 14:16:13 +0800 Message-ID: Subject: Re: [PATCH v5 5/7] mm: shmem: fix missing cache flush in shmem_mfill_atomic_pte() To: Mike Kravetz Cc: Andrew Morton , zi.yan@cs.rutgers.edu, "Kirill A. Shutemov" , David Rientjes , Lars Persson , Zi Yan , Linux Memory Management List , LKML , Xiongchun duan , Fam Zheng Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 70B5A180004 X-Stat-Signature: bjycaxeezspdts8mkfyry7ci43irze8m X-Rspam-User: Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b="v/JgsETL"; dmarc=pass (policy=none) header.from=bytedance.com; spf=pass (imf06.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.219.178 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com X-HE-Tag: 1644992211-329563 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Feb 16, 2022 at 3:12 AM Mike Kravetz wrote: > > On 2/10/22 04:30, Muchun Song wrote: > > The 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. > > > > 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 > > --- > > mm/shmem.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > Thanks, > > It might have been better to combine this and the next patch. When looking > at this, I noted the 'fallback to copy_from_user outside mmap_lock' case needs > to be addressed as well. It is in the next patch. No need to change. I separate those changes into 2 patches since the fixed patch is different. This patch is fixing linux 4.13 and later, while next patch is fixing linux 4.2 and later. Maybe it is hard to backport if combining those two patches. > > Reviewed-by: Mike Kravetz Thanks Mike.