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 DDC28C433FE for ; Thu, 7 Apr 2022 19:23:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229693AbiDGTZR (ORCPT ); Thu, 7 Apr 2022 15:25:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56992 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229626AbiDGTZQ (ORCPT ); Thu, 7 Apr 2022 15:25:16 -0400 Received: from mail-io1-xd29.google.com (mail-io1-xd29.google.com [IPv6:2607:f8b0:4864:20::d29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8200C270859 for ; Thu, 7 Apr 2022 12:23:13 -0700 (PDT) Received: by mail-io1-xd29.google.com with SMTP id 9so8060793iou.5 for ; Thu, 07 Apr 2022 12:23:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=l8OgFspqIU7b4vxeuPh92V4JMHLE7mkjNVSAXOwkoiI=; b=hqEsqkdUEZnH1z3sA9zbHCvR08eMANE+TcmOmjbDqr6CSsj75T6hADaySzUCuq0SeM w8EgXroBrA+8AiQz6o5psyA0BnEiA5dPpuNR5VWR5JMeOkqZYfSeU9xOJDozQ/6B7iTE EQEw0P1idXPRoOOjCOI0PDLVMOiRJSlqTlSm8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=l8OgFspqIU7b4vxeuPh92V4JMHLE7mkjNVSAXOwkoiI=; b=KLtJibUavvm+0+jFtqITQEdAPRRud4RyHoYY/9fNGprT2nHMEhV/0nzP4df0d82+yt 5d0YoXL+XVB/ybeEv7eUQQo/PzSRvtpcTlh3sMVk3WX6jECsXeDV8l/C9IY+C/MttR/e BMzS+yDjUR/StIzswVx/fHDvzUQZRAzdzKpfm9f6h1cs2oIbIK05cuixFfMfPMxDbeMM tkdKi9oiRSByw9rrwrfwzUbhtVc4cZg510l8YpbUnUcJpe5GBHkbIl5/B0qGwcaPEb0Z 0ro7JqCCH/8UKyWI79WmoH/RUD1MTdEa44Tbq9LG3mPGusPoVEAjtpCrGmkfQ6XMdb27 fnAw== X-Gm-Message-State: AOAM532KbjmJo6NKsoaK+Y2zjZ7Q8lCjOnIYsgbkOrAr58XhMk9AEgxj jFJeyJfgbVbc4K9zpzftbbFwfsf4LJYx1Q== X-Google-Smtp-Source: ABdhPJxo55dq2+4K1HsfVCjcmhVHiDxQKD4sjTU1sAei6R98e/vSm8ep5Z2aHOSWZ1QeDYi08Ztk2w== X-Received: by 2002:a05:6602:490:b0:638:c8ed:1e38 with SMTP id y16-20020a056602049000b00638c8ed1e38mr6848815iov.202.1649359392707; Thu, 07 Apr 2022 12:23:12 -0700 (PDT) Received: from [192.168.1.128] ([71.205.29.0]) by smtp.gmail.com with ESMTPSA id i12-20020a056e020ecc00b002ca53aba365sm5885794ilk.64.2022.04.07.12.23.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Apr 2022 12:23:11 -0700 (PDT) Subject: Re: [PATCH bpf-next] selftests/bpf: Fix return value checks in perf_event_stackmap.c To: Yuntao Wang , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Shuah Khan , Hengqi Chen , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Shuah Khan References: <20220407153814.104914-1-ytcoode@gmail.com> From: Shuah Khan Message-ID: <7ac36fbe-aa44-9311-320b-1e953c29a3c4@linuxfoundation.org> Date: Thu, 7 Apr 2022 13:23:10 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20220407153814.104914-1-ytcoode@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 4/7/22 9:38 AM, Yuntao Wang wrote: > The bpf_get_stackid() function may also return 0 on success. Can you add couple of sentences to describe what this patch does? bpf_get_stackid() may also return doesn't really say anything about why this patch is needed. > > Signed-off-by: Yuntao Wang > --- > tools/testing/selftests/bpf/progs/perf_event_stackmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/testing/selftests/bpf/progs/perf_event_stackmap.c b/tools/testing/selftests/bpf/progs/perf_event_stackmap.c > index b3fcb5274ee0..f793280a3238 100644 > --- a/tools/testing/selftests/bpf/progs/perf_event_stackmap.c > +++ b/tools/testing/selftests/bpf/progs/perf_event_stackmap.c > @@ -35,10 +35,10 @@ int oncpu(void *ctx) > long val; > > val = bpf_get_stackid(ctx, &stackmap, 0); > - if (val > 0) > + if (val >= 0) > stackid_kernel = 2; > val = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK); > - if (val > 0) > + if (val >= 0) > stackid_user = 2; > > trace = bpf_map_lookup_elem(&stackdata_map, &key); > Linux 5.18-rc1 shows a couple of more bpf_get_stackid() in this function. Removed in bpf-next - I assume. The change is good. I would like to see it explained better in the commit log. With the commit log fixed to explain why this change is needed and what happens if val equals to 0 condition isn't checked: Reviewed-by: Shuah Khan thanks, -- Shuah