From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3450821-1521219207-2-14408694881088386354 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521219206; b=i2zp8/vblDytUmZ02FCwfeF0p7DKn3UN0iguqj5vcldnUKD BpTLsnmK6P8iLvBf28/gR5IFFCzXyGF8aj3WXzGU02ejBQMeuaf6kIZWi7TO41zR NbnkJ+l9WuJkFOxuEF5kslcB2R+AnPvCiNvmuq/pdPUq+riKCLc5WN4kecM+4wnq 8JCpIMLx8vn5EqZKRT81A8OvJmAizTBbXhh7n4+D6YBuz6sTKt3VuHSihj1Sjv69 tOax3O0LIVvF4ISiu/eXUueq9ar6+lLZx/fjeEVcOk8yPd6JlOZk2dpAZMeBi6SW 6AlSgx3N+i1QMw/1EanNdrPgziP2fdu0SbWuZJg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1521219206; bh=TJCrpH1YFICbzakF9qYkANTEZK efpx0jmyAHUSGow0U=; b=CkuUmY5EeJ/j5il8qalkQviR20wU/7qxb7UQT046og EVWreDlpKBZH/7mSFoJDuGFgGO2fBGe5Op0ItHSk5FNyhAtQk+H7lZzpHm1WJr51 fuSkbzBv5X1IEL0eHgOUoZ99zWwfwueOkJIrpy4GX8c8tGot914W79TWdmRanbNj NzLqVJRVLpJdLAfGfNSZDO97MUigwAm7pZPW0tVLvdc7g3JACNxfbt0GkYfsUiHv MxTZUVZCz9jHRlxuvc+XACBq8VRPV9t4ZOb/UvFtW1viUVKQUa6TgK9Atd5BjNBW BPyxA/Ch58/5nmYSGpXFOMyTp+WK0pMDHdGIYtuK317A== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=kernel.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=orgdomain_pass; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kernel.org header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=kernel.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=orgdomain_pass; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=kernel.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751348AbeCPQxJ (ORCPT ); Fri, 16 Mar 2018 12:53:09 -0400 Received: from mx2.suse.de ([195.135.220.15]:52533 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752294AbeCPQxI (ORCPT ); Fri, 16 Mar 2018 12:53:08 -0400 Date: Fri, 16 Mar 2018 17:53:06 +0100 From: Michal Hocko To: Mike Kravetz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org, "Kirill A . Shutemov" , Nic Losby , Yisheng Xie , Andrew Morton , stable@vger.kernel.org Subject: Re: [PATCH v3] hugetlbfs: check for pgoff value overflow Message-ID: <20180316165306.GM23100@dhcp22.suse.cz> References: <20180306133135.4dc344e478d98f0e29f47698@linux-foundation.org> <20180309002726.7248-1-mike.kravetz@oracle.com> <20180316101757.GE23100@dhcp22.suse.cz> <12826dc6-c81e-c22a-2ec1-8e1cf0f07dfc@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12826dc6-c81e-c22a-2ec1-8e1cf0f07dfc@oracle.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri 16-03-18 09:19:07, Mike Kravetz wrote: > On 03/16/2018 03:17 AM, Michal Hocko wrote: > > On Thu 08-03-18 16:27:26, Mike Kravetz wrote: > > > > OK, looks good to me. Hairy but seems to be the easiest way around this. > > Acked-by: Michal Hocko > > > > >> +/* > >> + * Mask used when checking the page offset value passed in via system > >> + * calls. This value will be converted to a loff_t which is signed. > >> + * Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the > >> + * value. The extra bit (- 1 in the shift value) is to take the sign > >> + * bit into account. > >> + */ > >> +#define PGOFF_LOFFT_MAX (PAGE_MASK << (BITS_PER_LONG - (2 * PAGE_SHIFT) - 1)) > > Thanks Michal, > > However, kbuild found a problem with this definition on certain configs. > Consider a config where, > BITS_PER_LONG = 32 (32bit config) > PAGE_SHIFT = 16 (64K pages) > This results in the negative shift value. > Not something I would not immediately think of, but a valid config. Well, 64K pages on 32b doesn't sound even remotely sane to me but what ever. > The definition has been changed to, > #define PGOFF_LOFFT_MAX \ > (((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1))) > > as discussed here, > http://lkml.kernel.org/r/432fb2a3-b729-9c3a-7d60-890b8f9b10dd@oracle.com This looks more wild but seems correct as well. You can keep my acked-by Thanks! -- Michal Hocko SUSE Labs