From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta0.migadu.com (out-188.mta0.migadu.com [91.218.175.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBE5334CDD for ; Fri, 10 Jul 2026 15:15:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783696551; cv=none; b=S7MlJ2ceazWE4yRV3nO3Rmg6Dvmo2mC4zXaAj1Lf1Z8QzXeR1pmIT/x6Cwsir4xByzUTF5woSC80x+c4mjB+HV2vMRmzZ7UAGVDlZkOQtetfBPKuE7dCN32cTc09emEufTz3uS9cYVbP28zsjadrD0unJkIo3QMtyBwrGqqDv3s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783696551; c=relaxed/simple; bh=1Rd4oIKqX9SKQQHvtsM8kGWsJqTTLH5ZyMXq7FyonDA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lY9yzwVY0lk18v/K9T/e7oKn+xH7BGlBW/wu6FRh4lPuxp6G+cmvnx6nlOLbWAJJqWzjykOjjmvaoRKnYYWrPz/mBEW9y8qkcGympoZGdpDkEuTbA+0T4E5Xc7H2beKXMIeycZMmMYiER4hFM1CUUxZT6bmxzzjitpaeGguyIkc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=Wga810wc; arc=none smtp.client-ip=91.218.175.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="Wga810wc" Message-ID: <49cc5acf-24d4-4e1a-86a0-d05e29a75d42@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1783696531; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aF7FpZSUJmToTSbrChBipcg4Sj4NSH21xfjUv2dgBgk=; b=Wga810wcfj/NgzEW21KmkjBt0Z820hc8+vICWet+GqpHsLO+oBHTdNYJvy3TtcqzQEfxnj HhOp7aTi8Y4Y5GHQ1Jrzc5zdvypGyxhi8G+iLlvhOYxaz/muEpAN4D0btWI8Oad7ISk9/j JDvX8w0yomy58BeoP5nXFl0K9lJB6ow= Date: Fri, 10 Jul 2026 23:14:55 +0800 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next 2/2] selftests/bpf: Test fentry link after tracing_multi link To: sashiko-reviews@lists.linux.dev Cc: bpf@vger.kernel.org References: <20260710144734.78203-1-leon.hwang@linux.dev> <20260710144734.78203-3-leon.hwang@linux.dev> <20260710150412.5E8981F000E9@smtp.kernel.org> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Leon Hwang Content-Language: en-US In-Reply-To: <20260710150412.5E8981F000E9@smtp.kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2026/7/10 23:04, sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: > - [Medium] Test Flakiness due to Missing PID Filtering in BPF `fentry` Program > -- > > --- Patch [2]: [PATCH bpf-next 2/2] selftests/bpf: Test fentry link after tracing_multi link --- > commit 7dc95a7a3d3a0ca96e45e5ad2ebebe5157ae17ed > Author: Leon Hwang > > selftests/bpf: Test fentry link after tracing_multi link > > This commit adds a selftest to verify that an fentry link can be attached > safely after a tracing_multi link. It introduces a new fentry BPF program > and a corresponding user-space test case. > >> diff --git a/tools/testing/selftests/bpf/progs/tracing_multi_intersect_attach.c b/tools/testing/selftests/bpf/progs/tracing_multi_intersect_attach.c >> index cd5be0bb6ffdd..5ebbe3b602a4f 100644 >> --- a/tools/testing/selftests/bpf/progs/tracing_multi_intersect_attach.c >> +++ b/tools/testing/selftests/bpf/progs/tracing_multi_intersect_attach.c > > [ ... ] > >> @@ -11,6 +11,14 @@ __u64 test_result_fentry_1 = 0; >> __u64 test_result_fentry_2 = 0; >> __u64 test_result_fexit_1 = 0; >> __u64 test_result_fexit_2 = 0; >> +__u64 test_result_fentry = 0; >> + >> +SEC("fentry/bpf_fentry_test1") >> +int BPF_PROG(fentry, int a) >> +{ >> + test_result_fentry += a == 1; > > [Severity: Medium] > Can this cause test flakiness during parallel selftest runs? > > Because bpf_fentry_test1 is a global kernel function widely used across > various BPF selftests, parallel test executions might trigger this program. > Since the counter is incremented blindly without filtering by the executing > process PID, could parallel executions increase test_result_fentry above 1 > and cause the userland assertion ASSERT_EQ(skel->bss->test_result_fentry, 1) > to sporadically fail? > Correct. I should use tracing_multi_arg_check() here, which would filter the PID. Thanks, Leon >> + return 0; >> +} >> >> SEC("fentry.multi") >> int BPF_PROG(fentry_1) >