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 16174C433FE for ; Sun, 9 Oct 2022 12:53:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230116AbiJIMxx (ORCPT ); Sun, 9 Oct 2022 08:53:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229745AbiJIMxu (ORCPT ); Sun, 9 Oct 2022 08:53:50 -0400 Received: from mail-ej1-x629.google.com (mail-ej1-x629.google.com [IPv6:2a00:1450:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28308B492; Sun, 9 Oct 2022 05:53:49 -0700 (PDT) Received: by mail-ej1-x629.google.com with SMTP id d26so12841610eje.10; Sun, 09 Oct 2022 05:53:49 -0700 (PDT) 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:date:from:from:to:cc:subject:date:message-id:reply-to; bh=ZESD6ey7LAoCvYqteYGKHRcvT5xH2VgJgOZK6wnuVJU=; b=e47bf7q8ORFWnHRIliB9uWOqvqtG3S3kBFknWpss4c43ofG8tCdrrlYtL58iSXRY18 b/4QSouKbAmdBGaiq8ALf0RB+yY2d5XiF5FGxh8dsVyKKYYV0yLQb1igTeEaUyUZqH8S Pw+hm4PpC/lR2adpL1AX76ToB/ax5xPrRId8ivI76kOFbCsCPYo8q1P/Rhz7YuvOMzdF MGz7XKDjUQYgfCws6hM9vylH4b4+BgxmZa0ia+oCgeVoyhYacBnB+Kmw7T1uVBwDWJOv +/TzLofMv1+OaQk/nDbc4mCVBPhlr+E0eSjff3qAxHrD+mMGTw35sx0UruuxEBDajk4X 3hQQ== 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:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ZESD6ey7LAoCvYqteYGKHRcvT5xH2VgJgOZK6wnuVJU=; b=Hh9R7zxDJZEhNneemrFkSAbyE9+CL3LdV3YK03ireSDpcdYairwHaW0PSTAjMtsE51 Pog+tqQZdBpQcfB4nrVUZrgT2gSCCAeeAN7v5rMYcWaKPE50Pkeyjh3olR0d4GZHygGt dxlF20LdvNOf5mNjz8hRlvSgBOtSvHUDaEAY2+0Jj9TOwKhMBdnRkORpY6QzN1i//2WR xG+WGNtg5uW4WKcYTDdFgmF2E7Et999EkyPv+yQjIfv4PENnyvBY+dB3mKMeuQawWmoc TB2oomL5qd1BwVlsNqE2co89Qhf9Uc1rH060agIOdQrlvr/asxJ6qAVu7XW7LmGXg+RI AJNQ== X-Gm-Message-State: ACrzQf3gStD97q0/C0f8hbRUq04c7m8ZEI3lt3WB5AHEkMIlfd968N2P DtASi9yUEYQUIpeY6zWlP3k= X-Google-Smtp-Source: AMsMyM5QFoJMnh9+uhemwsIEXhMTcAfJqGRhBbH2BAqIf/LU/boRfqSxotDU3R/rhI3Cng/USX8iFw== X-Received: by 2002:a17:906:1e08:b0:73d:c724:4876 with SMTP id g8-20020a1709061e0800b0073dc7244876mr10975002ejj.62.1665320027534; Sun, 09 Oct 2022 05:53:47 -0700 (PDT) Received: from krava ([83.240.62.156]) by smtp.gmail.com with ESMTPSA id i24-20020a50d758000000b00458a03203b1sm5146741edj.31.2022.10.09.05.53.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Oct 2022 05:53:46 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Sun, 9 Oct 2022 14:53:42 +0200 To: Li kunyu Cc: lkp@intel.com, andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, haoluo@google.com, john.fastabend@gmail.com, kbuild-all@lists.01.org, kpsingh@kernel.org, linux-kernel@vger.kernel.org, martin.lau@linux.dev, sdf@google.com, song@kernel.org, yhs@fb.com Subject: Re: [PATCH] lib: bpf: Optimized variable usage in the btf_parse_elf function Message-ID: References: <202210082050.nPzAbV1v-lkp@intel.com> <20221009070827.525694-2-kunyu@nfschina.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221009070827.525694-2-kunyu@nfschina.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Oct 09, 2022 at 03:08:28PM +0800, Li kunyu wrote: > The following changes were made in the btf_parse_elf function: > 1. The initialization assignments of err, fd, scn and elf variables are > removed, and they do not affect function security after analysis. > 2. Remove unnecessary assignments to err variable (-error). > > Signed-off-by: Li kunyu > --- > tools/lib/bpf/btf.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c > index 2d14f1a52d7a..fa9d5fa03da4 100644 > --- a/tools/lib/bpf/btf.c > +++ b/tools/lib/bpf/btf.c > @@ -910,10 +910,10 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > struct btf_ext **btf_ext) > { > Elf_Data *btf_data = NULL, *btf_ext_data = NULL; > - int err = 0, fd = -1, idx = 0; > + int err, fd, idx = 0; > struct btf *btf = NULL; > - Elf_Scn *scn = NULL; > - Elf *elf = NULL; > + Elf_Scn *scn; > + Elf *elf; > GElf_Ehdr ehdr; > size_t shstrndx; > > @@ -924,9 +924,8 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > > fd = open(path, O_RDONLY | O_CLOEXEC); > if (fd < 0) { > - err = -errno; > pr_warn("failed to open %s: %s\n", path, strerror(errno)); > - return ERR_PTR(err); > + return ERR_PTR(-errno); hum, pr_warn could potentionally change errno jirka > } > > err = -LIBBPF_ERRNO__FORMAT; > @@ -987,8 +986,6 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > } > } > > - err = 0; > - > if (!btf_data) { > err = -ENOENT; > goto done; > -- > 2.18.2 >