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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 46713C41620 for ; Tue, 19 Jan 2021 14:57:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 166FE22241 for ; Tue, 19 Jan 2021 14:57:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391644AbhASOys (ORCPT ); Tue, 19 Jan 2021 09:54:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393638AbhASNA4 (ORCPT ); Tue, 19 Jan 2021 08:00:56 -0500 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48403C06179B for ; Tue, 19 Jan 2021 04:59:07 -0800 (PST) Received: by mail-qt1-x835.google.com with SMTP id e15so13527063qte.9 for ; Tue, 19 Jan 2021 04:59:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=B3Cy0Hm6xTRsmff/JkHOzD1P8m+ZaMSZbwZ78cwq0GQ=; b=ZGSI5bxWjU+x6vpwy6aJhb0H6QN8FxL1hxmj/KVTU1+omQptO3f8ci9LDt5IMdmEm1 c4v/0lgymC7G0E3l+2BOtcBk1DueLIbZR8J5cxMMLK3Yi0npvu/r/IIOp2wnIuuEiMOE DrJjzANZhdQ53CfuySR1LOimnUnSIDo4FGY/QmSEA0+i1UEodaNTu5jJ1/O7oInHnfdm qtOg4X7Kif7h5aJ2gi3ToQZLQMqsAQcD3DKwsenq41fiLGO26hoqLlrhFHOsM+1Ha+/8 g1zHKQfTf/f2IFzFEdXrbT2v96nn6w01sjb/AslAOhGMjo1PLV9/0FdTcZ/CTpaHjkXR P6zQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=B3Cy0Hm6xTRsmff/JkHOzD1P8m+ZaMSZbwZ78cwq0GQ=; b=RKkR2mSU/46d/Ck4fRBCk6jB1i0xX/yEJCJWFf0HSZS9uSVI/JaNdgno5edPKTvxi6 o7RHhowBuT8TWoVDos18ruj6/Oujr+NCTC2VehustKizB2iR2SucgR5bxekZjTsjeeT4 POWDfRd80X05tIkk0pPJAXhuv5B9QWO+Q15xNqaofr7v7545w4EuNnM51yURC7STTKbj FTgR99izDD14it93SX+BFGIZBLTogc1jO+NK+TzXbNl20qsq/B4rZhVEPNgZy0sPrZ1/ H0G/hO5dZ1pdKiOKRULYtjbzJMW/IHAK3l3B63bVrlehiWh1jBakVgYNkV5BdzDrDIJG sl8g== X-Gm-Message-State: AOAM531nfLoy1Bl0lNtfO9oaA1dPq9pLUHO5TeE9zJSG4z2EgiNXhuwQ pCN9u0Xr0YQNraAJUVxUvnfAjg== X-Google-Smtp-Source: ABdhPJwlbXLZsM8EZ3zbiuP95L7daX8Gjcn61F+rGmL6G3gAj59bCjoRgpcQVVChw0oLTnlsG4kHzA== X-Received: by 2002:a05:622a:4d1:: with SMTP id q17mr4030813qtx.272.1611061145938; Tue, 19 Jan 2021 04:59:05 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-115-133.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.115.133]) by smtp.gmail.com with ESMTPSA id k64sm13021228qkc.110.2021.01.19.04.59.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Jan 2021 04:59:05 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1l1qbA-003bfs-PA; Tue, 19 Jan 2021 08:59:04 -0400 Date: Tue, 19 Jan 2021 08:59:04 -0400 From: Jason Gunthorpe To: Douglas Gilbert Cc: Bodo Stroesser , linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, target-devel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, ddiss@suse.de, bvanassche@acm.org Subject: Re: [PATCH v6 1/4] sgl_alloc_order: remove 4 GiB limit, sgl_free() warning Message-ID: <20210119125904.GR4605@ziepe.ca> References: <20210118163006.61659-1-dgilbert@interlog.com> <20210118163006.61659-2-dgilbert@interlog.com> <20210118182854.GJ4605@ziepe.ca> <59707b66-0b6c-b397-82fe-5ad6a6f99ba1@interlog.com> <20210118202431.GO4605@ziepe.ca> <7f443666-b210-6f99-7b50-6c26d87fa7ca@gmail.com> <20210118234818.GP4605@ziepe.ca> <770a562e-52b9-ba93-59d3-1026340bf4f3@interlog.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <770a562e-52b9-ba93-59d3-1026340bf4f3@interlog.com> Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org On Mon, Jan 18, 2021 at 08:27:09PM -0500, Douglas Gilbert wrote: > To protect against the "unsigned long long" length being too big why > not pick a large power of two and if someone can justify a larger > value, they can send a patch. > > if (length > 64ULL * 1024 * 1024 * 1024) > return NULL; That is not how we protect against arithemetic overflows in the kernel Jason