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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 184F5C43460 for ; Tue, 13 Apr 2021 06:55:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F15AB613B6 for ; Tue, 13 Apr 2021 06:54:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236958AbhDMGzR (ORCPT ); Tue, 13 Apr 2021 02:55:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236828AbhDMGzP (ORCPT ); Tue, 13 Apr 2021 02:55:15 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3C49C061574 for ; Mon, 12 Apr 2021 23:54:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=rl7Av8z9Mb3AhGc2I2b/HfzYNKQlfkZtLSkmthxZ3Cs=; b=oXena5QrQsAuq/lXovE/vdznzG Zbnw2r9xxmldDA6+M9jB/+SFl853WgrhtbLlh7a+sWTsFgAEDytibwY8ygQJwRnj44+OSwPpQlAhB wLRDFznR8fpfuV7KYpgr20R93SPHj7ah/oFpN2O8fWd8+1X/hZLFDqIeNR6S1wQ1+//pSsxqJHO2C /+gfU1cAMp8iuXFAPdisVwcT0QDxckiECBBoWtjD94zP99pTR2jiaQ/lYsHrb20tTQAjHatpWRBIv xBgjcCOkLTBJf8PSKJz8TiitpXrQuOEwgajMbT2zHmaZZfcRqAhkJXL+cqsZRJoZv3X9nSV+A9o1R eVq7xOXg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lWCwU-008RVy-9U; Tue, 13 Apr 2021 06:54:40 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id E7E2C300036; Tue, 13 Apr 2021 08:54:33 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D8DCC2C4B2093; Tue, 13 Apr 2021 08:54:33 +0200 (CEST) Date: Tue, 13 Apr 2021 08:54:33 +0200 From: Peter Zijlstra To: Kees Cook Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org, x86@kernel.org, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, chris@chris-wilson.co.uk, intel-gfx@lists.freedesktop.org, linux-mm@kvack.org, hch@lst.de Subject: Re: [PATCH 6/7] i915: Convert to verify_page_range() Message-ID: References: <20210412080012.357146277@infradead.org> <20210412080611.902470568@infradead.org> <202104121306.3A73BEB0A5@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202104121306.3A73BEB0A5@keescook> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 12, 2021 at 01:08:38PM -0700, Kees Cook wrote: > On Mon, Apr 12, 2021 at 10:00:18AM +0200, Peter Zijlstra wrote: > > @@ -1249,14 +1249,14 @@ static int check_absent_pte(pte_t *pte, > > > > static int check_present(unsigned long addr, unsigned long len) > > { > > - return apply_to_page_range(current->mm, addr, len, > > - check_present_pte, (void *)addr); > > + return verify_page_range(current->mm, addr, len, > > + check_present_pte, (void *)addr); > > For example, switch to returning bad addr through verify_page_range(), > or have a by-reference value, etc: > > unsigned long failed; > > failed = verify_page_range(current->mm< addr, len, check_present_pte); > if (failed) { > pr_err("missing PTE:%lx\n", > (addr - failed) >> PAGE_SHIFT); OK, lemme try that.