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 0DF3AC4708E for ; Wed, 7 Dec 2022 12:19:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229515AbiLGMTl (ORCPT ); Wed, 7 Dec 2022 07:19:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbiLGMTl (ORCPT ); Wed, 7 Dec 2022 07:19:41 -0500 Received: from mail-ej1-x630.google.com (mail-ej1-x630.google.com [IPv6:2a00:1450:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31CE137239; Wed, 7 Dec 2022 04:19:40 -0800 (PST) Received: by mail-ej1-x630.google.com with SMTP id vv4so13590140ejc.2; Wed, 07 Dec 2022 04:19:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=CmvTqKRfXOeoURV/WIPlQ7bnJ0f1gD5Beg1+F1mUpNc=; b=cW6t/jpbIjWlAWC3U/V1Cs4laFfQKqbrnXK8gl3HFZymMIBqm3RPou+EUhZaiEn2BT 0U+/1VTkPBOR8KF/yzvzXwVf2TKidFJPG2m5gwyNfTj2oyqblLPeHpzf+qMJzUMv0tZE w/Zu5ZvfOuIjQOzy1Xc4cK8Uwb7jy9udzTjr5kmUP1EJHqOhgP0NSArwF8U+Nj8pXNzO 7ytU4APQp6lCkVZMFpzPYLiUZ+PySwiUg1H9wC2medjJvLN4ujb5ohAQlYeWDSazowMC bvqXP4yQkreqFrmFp3V6QP/5uBrEF5iijQ8Mw73nZv7E4WEKPlUiwStHnxjRXI9r2peE w/dQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=CmvTqKRfXOeoURV/WIPlQ7bnJ0f1gD5Beg1+F1mUpNc=; b=O9EDvzPqWNkEO50UQfadidCmOfeyhHI1XwghywKpGyJKxNPuc2De75XkcoZ1W2b62L v42EC+64oFt5UXHwjRJx/SO35SdvOD8rfpbIHHEIyIwazmp/MUUQ2a53gp0Thn9YvAZB c4zxUDIv1yzHl8QeItDGusejonMi8zbTvPwHQoIN9HEkqlfKeu4v/N6X8BjJlWQVODR0 7AIJfK8R848UrTR/c0I9/94/y868YS7MJG+6inU83Al+tDlVv6QyqfNGAeZy3T6l8cZs gSfKwO4N3AO9xGRtdvQgIurM9tbFcrKs029a+nvRYPtJy6HWcFaOW3fc0lq27D4j6Giu AktA== X-Gm-Message-State: ANoB5pnS2oGsRZDwjQCLZTXmTfreMTq4866BCl5mMDgHgwSvfg8tQZky yl600HS8fG0ewtX8LjzjvQXi+sUWPpA5vA== X-Google-Smtp-Source: AA0mqf710KJyubfBfFDRySyEWxRYlhvTHvDg5EqXEu6Ekf4TW3mQL/90vCxzymeGqShMkUfq2dWoQQ== X-Received: by 2002:a17:907:a688:b0:7ba:ba67:f2f with SMTP id vv8-20020a170907a68800b007baba670f2fmr51927784ejc.199.1670415578714; Wed, 07 Dec 2022 04:19:38 -0800 (PST) Received: from skbuf ([188.26.184.215]) by smtp.gmail.com with ESMTPSA id c10-20020a17090618aa00b007ad9c826d75sm8363992ejf.61.2022.12.07.04.19.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Dec 2022 04:19:38 -0800 (PST) Date: Wed, 7 Dec 2022 14:19:36 +0200 From: Vladimir Oltean To: Dan Carpenter Cc: "David S. Miller" , netdev@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH net] lib: packing: fix shift wrapping in bit_reverse() Message-ID: <20221207121936.bajyi5igz2kum4v3@skbuf> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Dec 07, 2022 at 02:23:28PM +0300, Dan Carpenter wrote: > The bit_reverse() function is clearly supposed to be able to handle > 64 bit values, but the types for "(1 << i)" and "bit << (width - i - 1)" > are not enough to handle more than 32 bits. > > Fixes: 554aae35007e ("lib: Add support for generic packing operations") > Signed-off-by: Dan Carpenter > --- > lib/packing.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/lib/packing.c b/lib/packing.c > index 9a72f4bbf0e2..9d7418052f5a 100644 > --- a/lib/packing.c > +++ b/lib/packing.c > @@ -32,12 +32,11 @@ static int get_reverse_lsw32_offset(int offset, size_t len) > static u64 bit_reverse(u64 val, unsigned int width) > { > u64 new_val = 0; > - unsigned int bit; > unsigned int i; > > for (i = 0; i < width; i++) { > - bit = (val & (1 << i)) != 0; > - new_val |= (bit << (width - i - 1)); > + if (val & BIT_ULL(1)) hmm, why 1 and not i? > + new_val |= BIT_ULL(width - i - 1); > } > return new_val; > } > -- > 2.35.1 >