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 X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51789C433E0 for ; Tue, 26 Jan 2021 06:49:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B2AE4206E5 for ; Tue, 26 Jan 2021 06:49:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B2AE4206E5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2B85A8D009C; Tue, 26 Jan 2021 01:49:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 240838D0076; Tue, 26 Jan 2021 01:49:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 10C138D009C; Tue, 26 Jan 2021 01:49:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0002.hostedemail.com [216.40.44.2]) by kanga.kvack.org (Postfix) with ESMTP id EB93C8D0076 for ; Tue, 26 Jan 2021 01:49:55 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B0AB5181AF5C3 for ; Tue, 26 Jan 2021 06:49:55 +0000 (UTC) X-FDA: 77747001150.23.drink16_59108602758c Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 926FC37609 for ; Tue, 26 Jan 2021 06:49:55 +0000 (UTC) X-HE-Tag: drink16_59108602758c X-Filterd-Recvd-Size: 5435 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 06:49:54 +0000 (UTC) Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DPy4K0Svxz15yXj; Tue, 26 Jan 2021 14:48:33 +0800 (CST) Received: from [10.174.179.117] (10.174.179.117) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.498.0; Tue, 26 Jan 2021 14:49:34 +0800 Subject: Re: [PATCH v11 02/13] mm: apply_to_pte_range warn and fail if a large pte is encountered To: Nicholas Piggin CC: , , , Jonathan Cameron , Christoph Hellwig , Christophe Leroy , Rick Edgecombe , Ding Tianhong , Christoph Hellwig , Linux-MM , Andrew Morton References: <20210126044510.2491820-1-npiggin@gmail.com> <20210126044510.2491820-3-npiggin@gmail.com> From: Miaohe Lin Message-ID: <4cb12137-2944-7973-b0f0-070f6f48bead@huawei.com> Date: Tue, 26 Jan 2021 14:49:34 +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: <20210126044510.2491820-3-npiggin@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.117] X-CFilter-Loop: Reflected 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: Hi: On 2021/1/26 12:44, Nicholas Piggin wrote: > apply_to_pte_range might mistake a large pte for bad, or treat it as a > page table, resulting in a crash or corruption. Add a test to warn and > return error if large entries are found. > > Reviewed-by: Christoph Hellwig > Signed-off-by: Nicholas Piggin > --- > mm/memory.c | 66 +++++++++++++++++++++++++++++++++++++++-------------- > 1 file changed, 49 insertions(+), 17 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index feff48e1465a..672e39a72788 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2440,13 +2440,21 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, > } > do { > next = pmd_addr_end(addr, end); > - if (create || !pmd_none_or_clear_bad(pmd)) { > - err = apply_to_pte_range(mm, pmd, addr, next, fn, data, > - create, mask); > - if (err) > - break; > + if (pmd_none(*pmd) && !create) > + continue; > + if (WARN_ON_ONCE(pmd_leaf(*pmd))) > + return -EINVAL; > + if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { > + if (!create) > + continue; > + pmd_clear_bad(pmd); > } > + err = apply_to_pte_range(mm, pmd, addr, next, > + fn, data, create, mask); > + if (err) > + break; > } while (pmd++, addr = next, addr != end); > + > return err; > } > > @@ -2468,13 +2476,21 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, > } > do { > next = pud_addr_end(addr, end); > - if (create || !pud_none_or_clear_bad(pud)) { > - err = apply_to_pmd_range(mm, pud, addr, next, fn, data, > - create, mask); > - if (err) > - break; > + if (pud_none(*pud) && !create) > + continue; > + if (WARN_ON_ONCE(pud_leaf(*pud))) > + return -EINVAL; > + if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) { > + if (!create) > + continue; > + pud_clear_bad(pud); > } > + err = apply_to_pmd_range(mm, pud, addr, next, > + fn, data, create, mask); > + if (err) > + break; > } while (pud++, addr = next, addr != end); > + > return err; > } > > @@ -2496,13 +2512,21 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, > } > do { > next = p4d_addr_end(addr, end); > - if (create || !p4d_none_or_clear_bad(p4d)) { > - err = apply_to_pud_range(mm, p4d, addr, next, fn, data, > - create, mask); > - if (err) > - break; > + if (p4d_none(*p4d) && !create) > + continue; > + if (WARN_ON_ONCE(p4d_leaf(*p4d))) > + return -EINVAL; > + if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) { > + if (!create) > + continue; > + p4d_clear_bad(p4d); > } > + err = apply_to_pud_range(mm, p4d, addr, next, > + fn, data, create, mask); > + if (err) > + break; > } while (p4d++, addr = next, addr != end); > + > return err; > } > > @@ -2522,9 +2546,17 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, > pgd = pgd_offset(mm, addr); > do { > next = pgd_addr_end(addr, end); > - if (!create && pgd_none_or_clear_bad(pgd)) > + if (pgd_none(*pgd) && !create) > continue; > - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask); > + if (WARN_ON_ONCE(pgd_leaf(*pgd))) > + return -EINVAL; > + if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) { > + if (!create) > + continue; > + pgd_clear_bad(pgd); > + } > + err = apply_to_p4d_range(mm, pgd, addr, next, > + fn, data, create, &mask); > if (err) > break; > } while (pgd++, addr = next, addr != end); > Looks good to me, thanks. Reviewed-by: Miaohe Lin