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 91A0DC433F5 for ; Wed, 19 Jan 2022 00:51:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EDF966B0071; Tue, 18 Jan 2022 19:51:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E8CF66B0073; Tue, 18 Jan 2022 19:51:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D554F6B0074; Tue, 18 Jan 2022 19:51:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0078.hostedemail.com [216.40.44.78]) by kanga.kvack.org (Postfix) with ESMTP id C2E866B0071 for ; Tue, 18 Jan 2022 19:51:51 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 65EA893668 for ; Wed, 19 Jan 2022 00:51:51 +0000 (UTC) X-FDA: 79045209222.27.D1DF0D3 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf05.hostedemail.com (Postfix) with ESMTP id 8D052100003 for ; Wed, 19 Jan 2022 00:51:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bSFNXBAL3L/sZMcUTYCHF8j9CNgzUTePNEfP42fi6WM=; b=ITKBmPkjINkr+kVaj6Y+dKIcDI BvqOngu/9IT5Rn4s9sTLn2PzesWshv2YBsi96+rofQ3+BVYoqVcjkMtC6rlUmPtTMSq/ul5NyOAI/ q9DfCSH+rEK9qqPiFSGY2rKngDe1XMI3RfAvmOn5EOBwbK7ns9ErE/q+y6JdyZZMHbSjln06B+F5d HQZHhSFi8mSfC9SP34IMzIrPdTN5zgIjUDjXMh1S7jqBjTqVUJ0QXKMfoUJYqorDpNzxB298VO7vG XIkw1MnizDFVQjXTcqksKReY9AwdDKZBSf1YV0Kkn1jYYD8jqYGonSDHHpgNXaVS+PGt16D+BzX3X cqw5cPlw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1n9zCB-009rPJ-HZ; Wed, 19 Jan 2022 00:51:27 +0000 Date: Wed, 19 Jan 2022 00:51:27 +0000 From: Matthew Wilcox To: Yury Norov Cc: Catalin Marinas , Will Deacon , Andrew Morton , Nicholas Piggin , Ding Tianhong , Anshuman Khandual , Alexey Klimov , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Uladzislau Rezki Subject: Re: [PATCH] vmap(): don't allow invalid pages Message-ID: References: <20220118235244.540103-1-yury.norov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220118235244.540103-1-yury.norov@gmail.com> X-Rspamd-Queue-Id: 8D052100003 X-Stat-Signature: urcktm3bxtjxokutccw7nr148euaua61 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=ITKBmPkj; dmarc=none; spf=none (imf05.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspamd-Server: rspam06 X-HE-Tag: 1642553510-564385 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 Tue, Jan 18, 2022 at 03:52:44PM -0800, Yury Norov wrote: > vmap() takes struct page *pages as one of arguments, and user may provide > an invalid pointer which would lead to DABT at address translation later. Could we spell out 'DABT'? Presumably that's an ARM-specific thing. Just like we don't say #PF for Intel page faults, I think this is probably a 'data abort'? > Currently, kernel checks the pages against NULL. In my case, however, the > address was not NULL, and was big enough so that the hardware generated > Address Size Abort on arm64. > > Interestingly, this abort happens even if copy_from_kernel_nofault() is > used, which is quite inconvenient for debugging purposes. > > This patch adds a pfn_valid() check into vmap() path, so that invalid > mapping will not be created. > > RFC: https://lkml.org/lkml/2022/1/18/815 > v1: use pfn_valid() instead of adding an arch-specific > arch_vmap_page_valid(). Thanks to Matthew Wilcox for the hint. > > Signed-off-by: Yury Norov Suggested-by: Matthew Wilcox (Oracle) > --- > mm/vmalloc.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index d2a00ad4e1dd..a4134ee56b10 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -477,6 +477,8 @@ static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr, > return -EBUSY; > if (WARN_ON(!page)) > return -ENOMEM; > + if (WARN_ON(!pfn_valid(page_to_pfn(page)))) > + return -EINVAL; > set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); > (*nr)++; > } while (pte++, addr += PAGE_SIZE, addr != end); > -- > 2.30.2 >