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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 DB636C4708D for ; Fri, 28 May 2021 21:13:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4E6A613B4 for ; Fri, 28 May 2021 21:13:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229620AbhE1VPV (ORCPT ); Fri, 28 May 2021 17:15:21 -0400 Received: from www62.your-server.de ([213.133.104.62]:41710 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229481AbhE1VPU (ORCPT ); Fri, 28 May 2021 17:15:20 -0400 Received: from sslproxy03.your-server.de ([88.198.220.132]) by www62.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1lmjNA-0000UR-78; Fri, 28 May 2021 22:46:24 +0200 Received: from [85.7.101.30] (helo=linux.home) by sslproxy03.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lmjNA-000JT2-0a; Fri, 28 May 2021 22:46:24 +0200 Subject: Re: [PATCH] selftests/bpf: Fix return value check in attach_bpf() To: Yu Kuai , shuah@kernel.org, ast@kernel.org, andrii@kernel.org Cc: linux-kselftest@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com References: <20210528090758.1108464-1-yukuai3@huawei.com> From: Daniel Borkmann Message-ID: Date: Fri, 28 May 2021 22:46:23 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20210528090758.1108464-1-yukuai3@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.103.2/26184/Fri May 28 13:05:50 2021) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/28/21 11:07 AM, Yu Kuai wrote: > use libbpf_get_error() to check the return value of > bpf_program__attach(). > > Reported-by: Hulk Robot > Signed-off-by: Yu Kuai > --- > tools/testing/selftests/bpf/benchs/bench_rename.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/benchs/bench_rename.c b/tools/testing/selftests/bpf/benchs/bench_rename.c > index c7ec114eca56..b7d4a1d74fca 100644 > --- a/tools/testing/selftests/bpf/benchs/bench_rename.c > +++ b/tools/testing/selftests/bpf/benchs/bench_rename.c > @@ -65,7 +65,7 @@ static void attach_bpf(struct bpf_program *prog) > struct bpf_link *link; > > link = bpf_program__attach(prog); > - if (!link) { > + if (libbpf_get_error(link)) { > fprintf(stderr, "failed to attach program!\n"); > exit(1); > } Could you explain the rationale of this patch? bad2e478af3b ("selftests/bpf: Turn on libbpf 1.0 mode and fix all IS_ERR checks") explains: 'Fix all the explicit IS_ERR checks that now will be broken because libbpf returns NULL on error (and sets errno).' So the !link check looks totally reasonable to me. Converting to libbpf_get_error() is not wrong in itself, but given you don't make any use of the err code, there is also no point in this diff here. Thanks, Daniel