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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49445C433FE for ; Sat, 8 Oct 2022 03:21:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229437AbiJHDVy (ORCPT ); Fri, 7 Oct 2022 23:21:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55364 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbiJHDVk (ORCPT ); Fri, 7 Oct 2022 23:21:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 341D211B2DF; Fri, 7 Oct 2022 20:21:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id CC1B3B82430; Sat, 8 Oct 2022 03:21:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5142DC433C1; Sat, 8 Oct 2022 03:21:30 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="QJwXB42z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1665199288; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=L9NKrsR7tTYpbn5X6JuYO0fYdKTzEIaHBiFinguj7aw=; b=QJwXB42zql9DO3ci56fK0qdt3KETO02OTgln46NrLRebl+kAFg75irZufDkHzEZwB29CpM Ubvcrjo1Rpn2o0HxsDqhv3cZBSXnbxayqkMXN0QW7oMK5AxmGenYUT0yhLgOQDZCQVHQgc pmnnlQLP6smI8ZrGrciXPoRUntBuJe8= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id ea268ade (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sat, 8 Oct 2022 03:21:28 +0000 (UTC) Date: Fri, 7 Oct 2022 21:21:20 -0600 From: "Jason A. Donenfeld" To: Kees Cook Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev, Andreas Noever , Andrew Morton , Andy Shevchenko , Borislav Petkov , Catalin Marinas , Christoph =?utf-8?Q?B=C3=B6hmwalder?= , Christoph Hellwig , Christophe Leroy , Daniel Borkmann , Dave Airlie , Dave Hansen , "David S . Miller" , Eric Dumazet , Florian Westphal , Greg Kroah-Hartman , "H . Peter Anvin" , Heiko Carstens , Helge Deller , Herbert Xu , Huacai Chen , Hugh Dickins , Jakub Kicinski , "James E . J . Bottomley" , Jan Kara , Jason Gunthorpe , Jens Axboe , Johannes Berg , Jonathan Corbet , Jozsef Kadlecsik , KP Singh , Marco Elver , Mauro Carvalho Chehab , Michael Ellerman , Pablo Neira Ayuso , Paolo Abeni , Peter Zijlstra , Richard Weinberger , Russell King , Theodore Ts'o , Thomas Bogendoerfer , Thomas Gleixner , Thomas Graf , Ulf Hansson , Vignesh Raghavendra , WANG Xuerui , Will Deacon , Yury Norov , dri-devel@lists.freedesktop.org, kasan-dev@googlegroups.com, kernel-janitors@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-crypto@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-mmc@vger.kernel.org, linux-mtd@lists.infradead.org, linux-nvme@lists.infradead.org, linux-parisc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, netdev@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, Jan Kara Subject: Re: [PATCH v4 2/6] treewide: use prandom_u32_max() when possible Message-ID: References: <20221007180107.216067-1-Jason@zx2c4.com> <20221007180107.216067-3-Jason@zx2c4.com> <202210071241.445289C5@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <202210071241.445289C5@keescook> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Oct 07, 2022 at 03:47:44PM -0700, Kees Cook wrote: > > diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c > > index 4f2f2d1bac56..56ffaa8dd3f6 100644 > > --- a/lib/test_vmalloc.c > > +++ b/lib/test_vmalloc.c > > @@ -151,9 +151,7 @@ static int random_size_alloc_test(void) > > int i; > > > > for (i = 0; i < test_loop_count; i++) { > > - n = prandom_u32(); > > - n = (n % 100) + 1; > > - > > + n = prandom_u32_max(n % 100) + 1; > > p = vmalloc(n * PAGE_SIZE); > > > > if (!p) > > This looks wrong. Cocci says: > > - n = prandom_u32(); > - n = (n % 100) + 1; > + n = prandom_u32_max(100) + 1; I agree that's wrong, but what rule did you use to make Cocci generate that? Jason