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_CR_TRAILER, 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 67706C47089 for ; Wed, 26 May 2021 19:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4182D613C3 for ; Wed, 26 May 2021 19:21:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233726AbhEZTXI (ORCPT ); Wed, 26 May 2021 15:23:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232155AbhEZTW7 (ORCPT ); Wed, 26 May 2021 15:22:59 -0400 Received: from mail-qt1-x829.google.com (mail-qt1-x829.google.com [IPv6:2607:f8b0:4864:20::829]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C22FC061574 for ; Wed, 26 May 2021 12:21:26 -0700 (PDT) Received: by mail-qt1-x829.google.com with SMTP id t20so1748642qtx.8 for ; Wed, 26 May 2021 12:21:26 -0700 (PDT) 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=wI7tCNlcaTZmqH6g95a10WXByiu3PTAxzCVAG5uZNco=; b=SM3f/vu2XiZrKAcI7L4W7BwbiSvj1ehZ0sxFk5BfEzmHNgjVe7BHFB9U6lkCE01h52 kWEj+xQnqO7fceVIc2CwmBHvDYJ536FMFmcdKNZhH/szoBmrBsS6sLB5dhe67VtEQKbn ST0HkTO80trrnBilylR/5H7rQWiV/D4neNsVX08dKvlmnSM5n9ILkC1OsbKyJEHy+nt0 Iju4cArPuwH2Jn/2vznanYAbqSchzzPwXeQPyRid9E4ckMXp8xMY/WUBaWy2kEBavbX6 kOhCdvm98E6NzV8ZdCN2VpIvQ+jeilVyKIm5X4kZ0xl87sngJOcVnbb6bzVSPNz0rwj1 hSEw== 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=wI7tCNlcaTZmqH6g95a10WXByiu3PTAxzCVAG5uZNco=; b=S3FGxHHLDy+v575OoeVIObKETZt0wqoaJOBuY3LYkN9oz0b4jTsibH04rT/bAyrXMF AF2Fv/kfTMdVHamNOp/QD8367on4s5xB/yR9OKKLsNRjtV42l8ZifhBbH+eakaBGfRM6 r5xr/3X+PWNtamPtq+z10G22VByYnttqCllJ8qFKcIFDQbkS5f8qHNxdATIX+mI23wje wNoGdHCYM4zsCTAeVtltQVBOmCmPR1CFYiu01U95vPOl/2pNnqdOVD5JcBaQ9XOYFM+D 2Pm3jK81N2PE+6pO2vXkGDnl3e4zh0ra22bF7AC8t6Q6HMB3Jo/oq6fUotu/1q8MkQwi ecXQ== X-Gm-Message-State: AOAM532ofIrO7a4gNv9p2Th/xes1ObmSGnPJbjcaR+G/nRpgt9E+wdlz Hu2l5vHNRujJ/nkrFWOLbU2RKg== X-Google-Smtp-Source: ABdhPJx3twK2Z0UVhtntwGDvGoua/9nmaJnAFQUJsqgCit0fyMZoTch2+UM/cuyHcYXCcGgh630hfw== X-Received: by 2002:ac8:4a0a:: with SMTP id x10mr17715979qtq.201.1622056885353; Wed, 26 May 2021 12:21:25 -0700 (PDT) Received: from ziepe.ca ([206.223.160.26]) by smtp.gmail.com with ESMTPSA id 127sm2172724qkl.116.2021.05.26.12.21.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 May 2021 12:21:24 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1llz5n-00FI2b-Re; Wed, 26 May 2021 16:21:23 -0300 Date: Wed, 26 May 2021 16:21:23 -0300 From: Jason Gunthorpe To: Colin King Cc: =?utf-8?B?SsOpcsO0bWU=?= Glisse , Andrew Morton , Ralph Campbell , Stephen Rothwell , Alistair Popple , linux-mm@kvack.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][V2][next] mm: selftests: fix potential integer overflow on shift of a int Message-ID: <20210526192123.GE1096940@ziepe.ca> References: <20210526170530.3766167-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210526170530.3766167-1-colin.king@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 26, 2021 at 06:05:30PM +0100, Colin King wrote: > From: Colin Ian King > > The left shift of the int mapped is evaluated using 32 bit arithmetic > and then assigned to an unsigned long. In the case where mapped is > 0x80000 when PAGE_SHIFT is 12 will lead to the upper bits being > sign extended in the unsigned long. Larger values can lead to an > int overflow. Avoid this by making mapped an unsigned long. > > Addresses-Coverity: ("Uninitentional integer overflow") > Fixes: 8b2a105c3794 ("mm: selftests for exclusive device memory") > Signed-off-by: Colin Ian King > --- > > V2: Make mapped an unsigned long rather than casting it to unsigned long Reviewed-by: Jason Gunthorpe Jason