From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 843333A1E71 for ; Tue, 24 Feb 2026 15:24:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771946642; cv=none; b=GNoB8WQxnSaWXEyI7CmbrCHwsXCfUz34axaE94gNhNr65V7l4e73Tm3AHdizVv2kHLy8chA53UtoziUsIX97J4W+IlmIFXECotAn+w73jPZ8uM61MsKTCIxoQ8HqfeZOBzaVh4pKOYncp7DFISXGswSgJSNIdI+oCwkoFWi7N6c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771946642; c=relaxed/simple; bh=UrTaP6oGvX5uJJoKd5IjdgYHjmOEKQFLa1uREBRJhuE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ECLTfXO4r0i6zQpQd/iUuAcbyWpktusA3HQ/ANgq/Jpy/+fsVEv8zIThrPSBj4K9gNOEgBjhrN5PihpPGb9/DcdQMd656WrT5EWNqxjyo1qZK5sDNxga7kTOwqGMxH8nu1CCykPInjG0H8e+5onG9/7fFGqNV8cHL+A6JuaeddU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=EtTdvVFK; arc=none smtp.client-ip=209.85.128.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="EtTdvVFK" Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-483703e4b08so45244915e9.1 for ; Tue, 24 Feb 2026 07:24:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1771946639; x=1772551439; darn=vger.kernel.org; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:from:to:cc:subject:date:message-id:reply-to; bh=ZP4AMy1sqSeWM2NP0BWkcgG45AN7Tm9+i3BZPKHn4+0=; b=EtTdvVFKvDs2GXW4GBI2lbMD7VwAc5rxPBC10PDkJf4Yz8n1rmrIsmG6Ovd1k36Gn8 41ekeAo48fwZgEv9vAtoanQzY5DaFrXzqcXb4TFe2n3E7635tX36PVsO1asvOMtb4lBq GX11t6nVz+YchofsLVhkU8IMv4fL2gZWs7S0Gup0rUtX2WSgsYOVyTMND9vBmptVNXS3 /UEnS65T13ZM/CALh4L9NxceoVSG8zoDXf7lCMsklOLyZZcTKO+c1vkkxQAVUIAMXZad CHUkVvR8BvbzuT1qbKiBimK+BycMzOHhUI1y1qF0lR9BvBI07Hnr162e1tUwVFRvrSk8 eNlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771946639; x=1772551439; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ZP4AMy1sqSeWM2NP0BWkcgG45AN7Tm9+i3BZPKHn4+0=; b=tqnI5OCX/J6Ya3XqVrZBuBXYTyM5r0ieJjYqryFz6csJqlDlU1Tx/tz5AgPQnRN5zD Iy+47BffTBYUJPKttgGehF7JlI3nKxmILdJZ1mEicJ+K17kKimDba6Kb66ZJMEEfbu8a VDRBYbP8402KSu/qGJXEi4tY1/xWdtOtVhqy8WLXAF9Dd3JTblY4kmZfCbSLskLuclCY 8aaJKdTm86zjwX7acmBb5PfJGia2cN78ahOj9d5wDRT0GDonyZFOWxsXaGLU98YhlCnZ JHq6S0it5m6GB6OfIPBa6fQOHJyJlS4qIjJXytfLLaFhSGqGgHlWQ1itkQtbnbwjwjCb BUvQ== X-Gm-Message-State: AOJu0YxhMyjtZ3RQoTBaciO2Me+/cnBlaq53tudApklNdM8MXS8YdXKN MtUysybR6i/2QkmjiYiUg+s14yKpMs349UVfZcmStmwLF042F2yksKRH X-Gm-Gg: AZuq6aJEvysHucFvAmHpGUMJoujxfwwABushQQeZQ+ZbHODrRZV3IHUMt9kdmzO15qv Dfem90B6mm89aSqhuPj2SsQe2qs4qAncldjxjkA1bxgfCLa4EBaOAekf5Zzh2woNINYuS8ijVJ5 FVEbBH0wfQWQBT8GVv6xV8I+ht7hVHtbx62PR8QlBHPq1EiF8dJnmpXH9RGr1f2Cl8iVKzJZVjc Qzukj9hYbRk9bgQYneMRbqlJ3bQdn7o8WTLBfg/CGTve2VTdqjQGFuVsjvTcT3e9YvdCcd1p07q cL6FF/iVNlhmxgRASCDHqukBoukTk2DeuDDvhaJx+JYprJIUOcFH5IWOKz9PKMZd6Tp9JNsi4C8 nOyJiF+VDQHa1WdAWtVY3VwSta5bBmhulMDinTUXuQnnf/V/64XK0Vl3hnibI7Mj1yke6dBs5ZI T+aM/R6HO/O2jtm4WQB2o= X-Received: by 2002:a05:600c:630d:b0:483:7ea3:3de3 with SMTP id 5b1f17b1804b1-483bd7245ffmr5740345e9.2.1771946638621; Tue, 24 Feb 2026 07:23:58 -0800 (PST) Received: from localhost ([2620:10d:c092:500::7:95aa]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-483bd6854c7sm18059045e9.0.2026.02.24.07.23.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Feb 2026 07:23:58 -0800 (PST) From: Mykyta Yatsenko To: Ihor Solodrai , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Eduard Zingerman , Amery Hung Cc: bpf@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH bpf-next v1] selftests/bpf: Fix flakiness of task_local_storage/sys_enter_exit In-Reply-To: <20260224015855.1481707-1-ihor.solodrai@linux.dev> References: <20260224015855.1481707-1-ihor.solodrai@linux.dev> Date: Tue, 24 Feb 2026 15:23:57 +0000 Message-ID: <87v7fmb1wy.fsf@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Ihor Solodrai writes: > The test_sys_enter_exit test was setting target_pid before attaching > the BPF programs, which causes syscalls made during the attach phase > to be counted. This is flaky because, apparently, there is no > guarantee that both on_enter and on_exit will trigger during the > attachment. > > Move the target_pid assignment to after task_local_storage__attach() > so that only explicit sys_gettid() calls are counted. > > Reported-by: BPF CI Bot (Claude Opus 4.6) > Closes: https://github.com/kernel-patches/vmtest/issues/448 > Signed-off-by: Ihor Solodrai > > --- > > I've been experimenting with running AI on BPF CI to investigate test > failures. This is an example of a thing it may come up with. > > I don't want to spam the list with these, so for starters I'll be > relaying only patches that I evaluated and/or tested. > > The AI generated reports will be posted with "[bpf-ci-bot]" prefix > here: https://github.com/kernel-patches/vmtest/issues > > The goal of this particular application of AI is to make BPF CI more > stable, less noisy/flaky, and potentially find and fix more kernel > bugs. We'll see how it goes. > > --- > .../selftests/bpf/prog_tests/task_local_storage.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c > index 7bee33797c71..2820a604aaa6 100644 > --- a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c > +++ b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c > @@ -25,24 +25,28 @@ > static void test_sys_enter_exit(void) > { > struct task_local_storage *skel; > + pid_t pid = sys_gettid(); > int err; > > skel = task_local_storage__open_and_load(); > if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) > return; > > - skel->bss->target_pid = sys_gettid(); > - > err = task_local_storage__attach(skel); > if (!ASSERT_OK(err, "skel_attach")) > goto out; > > + /* Set target_pid after attach so that syscalls made during > + * attach are not counted. > + */ > + skel->bss->target_pid = pid; > + > sys_gettid(); > sys_gettid(); Maybe a simpler and less fragile fix would be to add syscall number filter in the BPF program, so that we don't count those unexpected syscalls. > > - /* 3x syscalls: 1x attach and 2x gettid */ > - ASSERT_EQ(skel->bss->enter_cnt, 3, "enter_cnt"); > - ASSERT_EQ(skel->bss->exit_cnt, 3, "exit_cnt"); > + /* 2x gettid syscalls */ > + ASSERT_EQ(skel->bss->enter_cnt, 2, "enter_cnt"); > + ASSERT_EQ(skel->bss->exit_cnt, 2, "exit_cnt"); > ASSERT_EQ(skel->bss->mismatch_cnt, 0, "mismatch_cnt"); > out: > task_local_storage__destroy(skel); > -- > 2.53.0