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 9DE83C433EF for ; Wed, 13 Jul 2022 02:11:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A18289400F2; Tue, 12 Jul 2022 22:11:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9A0349400E5; Tue, 12 Jul 2022 22:11:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 841C89400F2; Tue, 12 Jul 2022 22:11:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 71DCF9400E5 for ; Tue, 12 Jul 2022 22:11:03 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id 3E233120827 for ; Wed, 13 Jul 2022 02:11:03 +0000 (UTC) X-FDA: 79680448806.13.D5C8DA0 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf08.hostedemail.com (Postfix) with ESMTP id 8035A160054 for ; Wed, 13 Jul 2022 02:11:01 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LjLdT3r0tzkWbm; Wed, 13 Jul 2022 10:08:45 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 13 Jul 2022 10:10:56 +0800 Subject: Re: [PATCH] mm/hugetlb: avoid corrupting page->mapping in hugetlb_mcopy_atomic_pte To: Mike Kravetz CC: , , Axel Rasmussen , Peter Xu , , References: <20220712130542.18836-1-linmiaohe@huawei.com> From: Miaohe Lin Message-ID: <1f9e8378-f61c-5bfe-1c47-fbaf0dc4f51a@huawei.com> Date: Wed, 13 Jul 2022 10:10:56 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657678262; a=rsa-sha256; cv=none; b=ZviZcFHyMMCkpInp+UfQHPxB4QF0ERx6Abc82DYpbVQvMmuEw+fR4Y+qzqoOAh5mUMnnGx N5Qsexfd4x577PmE2+uNxNUYd0fgUIMk/Z3zK0ekVpB3TkM/TsOrX6lt7y2gCL40FUkkN+ FUo3me7r69O9KQVrRnwRDgQlIFsWDzM= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657678262; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vhv709XL0kRp8N1QSkIIRV+EuHRRQNRR058GHmzY+zI=; b=Bw9EuhXKwWap/Va7jL2NN+guh/KOD5u7xB5ErOgr9+99Yxlh9OaWZPo5HTz1vzAIGhcIfX H7Mh2SS/3ppUlI8P7jXr7N+VOV0m4L84Q39+Z/fBzoMSpoofbXc8eHyCvFdSYDy70tec4N HzstN5sH7PLr6b6GXU2WMcLSTL9c8Tw= X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 8035A160054 X-Rspam-User: Authentication-Results: imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Stat-Signature: 8orezrn3owpxmw71s9qai5q6ed1fzf71 X-HE-Tag: 1657678261-982283 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 2022/7/13 1:39, Mike Kravetz wrote: > On 07/12/22 21:05, Miaohe Lin wrote: >> In MCOPY_ATOMIC_CONTINUE case with a non-shared VMA, pages in the page >> cache are installed in the ptes. But hugepage_add_new_anon_rmap is called >> for them mistakenly because they're not vm_shared. This will corrupt the >> page->mapping used by page cache code. >> >> Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl") >> Signed-off-by: Miaohe Lin >> --- >> mm/hugetlb.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > This looks correct to me. > > Reviewed-by: Mike Kravetz Many thanks for review. > > However, I am having a hard time wrapping my head around how UFFDIO_CONTINUE > should work on non-anon private mappings. For example, a private mapping of > a hugetlbfs file. I think we just map the page in the file/cache and do not > set the write bit in the pte. So, yes we would want page_dup_file_rmap() > in this case as shown below. +1 > > Adding Axel and Peter on Cc: as they were more involved in adding that code > and the design of UFFDIO_CONTINUE. That would be really helpful. Thanks. >