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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 D0446C2D0A3 for ; Wed, 4 Nov 2020 00:47:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 184D9223EA for ; Wed, 4 Nov 2020 00:47:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="UwvoZx12" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 184D9223EA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 32A1F6B005C; Tue, 3 Nov 2020 19:47:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2B33F6B005D; Tue, 3 Nov 2020 19:47:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 17A066B0068; Tue, 3 Nov 2020 19:47:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0052.hostedemail.com [216.40.44.52]) by kanga.kvack.org (Postfix) with ESMTP id D3A276B005C for ; Tue, 3 Nov 2020 19:47:11 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 33918180AD801 for ; Wed, 4 Nov 2020 00:47:11 +0000 (UTC) X-FDA: 77444896662.24.bread28_1b0fc28272bd Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 135611A4A0 for ; Wed, 4 Nov 2020 00:47:11 +0000 (UTC) X-HE-Tag: bread28_1b0fc28272bd X-Filterd-Recvd-Size: 2434 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Wed, 4 Nov 2020 00:47:10 +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=X4oXEmqPJYPSNCqi6icSPg/r0ar5c+Km4ETiScfHMIk=; b=UwvoZx12QP+3fOmliXDZdGsHDC 5e2g1Ztzp9tcWtenw7exu5wGyCMvleib7pcjIJF1TKupfRAo5OzqSU+zsltQ6dycb97jWcoDgrvAn OMZ+pbeuCMtJ8GXVpq/O5ytnPxaSilBN9XT+6Jysi2hBnZ+ClQRtk4LURExYRdUaNkWHGbyKvFDrP O80udmJ+0iiBwnAsx8PfQ4LCkE6PxjB4FhvDj+i7NqGN+x+QCrP2llfYuG2fR0BRhroI4w7xvfAle SQpmAOXoNLmoth/UmD5kRjB5WCThBTig9jsuTYJKOY0Jw++9KOVoX/I4cUCG2xL45Uw5vihN+CSpM poBSD19A==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ka6x7-0005I1-Ea; Wed, 04 Nov 2020 00:47:05 +0000 Date: Wed, 4 Nov 2020 00:47:05 +0000 From: Matthew Wilcox To: Andrew Morton Cc: hsinhuiwu@gmail.com, bugzilla-daemon@bugzilla.kernel.org, linux-mm@kvack.org Subject: Re: [Bug 210023] New: Crash when allocating > 2 TB memory Message-ID: <20201104004705.GJ27442@casper.infradead.org> References: <20201103162740.6a7c835276b5a704d5b219cc@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201103162740.6a7c835276b5a704d5b219cc@linux-foundation.org> 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, Nov 03, 2020 at 04:27:40PM -0800, Andrew Morton wrote: > const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; > unsigned int nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; > - unsigned int array_size = nr_pages * sizeof(struct page *), i; > + unsigned long array_size > + unsigned int i; > struct page **pages; > > + array_size = (unsigned long)nr_pages * sizeof(struct page *); This is only pushing the problem out ~5 years. If somebody tries to allocate a 16TB area, 16TB / 4kB is 4GB and nr_pages overflows. That's only 3 doublings of RAM away. I think we need to change vm_struct's nr_pages from an unsigned int to an unsigned long. It won't take up any more room because it's sandwiched between a pointer and a phys_addr_t.