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 04ED2C433F5 for ; Thu, 26 May 2022 11:33:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3C1C18D0003; Thu, 26 May 2022 07:33:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3706B8D0001; Thu, 26 May 2022 07:33:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 25A2C8D0003; Thu, 26 May 2022 07:33:52 -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 168798D0001 for ; Thu, 26 May 2022 07:33:52 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id D8EB080364 for ; Thu, 26 May 2022 11:33:51 +0000 (UTC) X-FDA: 79507684662.18.EC05C01 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf08.hostedemail.com (Postfix) with ESMTP id D6B76160038 for ; Thu, 26 May 2022 11:33:25 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4L85Qd30kxzjWvn; Thu, 26 May 2022 19:32:57 +0800 (CST) Received: from huawei.com (10.175.124.27) 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; Thu, 26 May 2022 19:33:41 +0800 From: Miaohe Lin To: , CC: , , , Subject: [PATCH] mm/page_table_check: fix accessing unmapped ptep Date: Thu, 26 May 2022 19:33:50 +0800 Message-ID: <20220526113350.30806-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: D6B76160038 X-Stat-Signature: 54btjecpbxzdsuu7gjhwynbfw9n1yn7y Authentication-Results: imf08.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf08.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-Rspam-User: X-HE-Tag: 1653564805-318865 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: ptep is unmapped too early, so ptep will be accessed while it's unmapped. Fix it by deferring pte_unmap() until page table checking is done. Fixes: 80110bbfbba6 ("mm/page_table_check: check entries at pmd levels") Signed-off-by: Miaohe Lin --- mm/page_table_check.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_table_check.c b/mm/page_table_check.c index 3692bea2ea2c..971c3129b0e3 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -234,11 +234,11 @@ void __page_table_check_pte_clear_range(struct mm_struct *mm, pte_t *ptep = pte_offset_map(&pmd, addr); unsigned long i; - pte_unmap(ptep); for (i = 0; i < PTRS_PER_PTE; i++) { __page_table_check_pte_clear(mm, addr, *ptep); addr += PAGE_SIZE; ptep++; } + pte_unmap(ptep); } } -- 2.23.0