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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA455C05027 for ; Thu, 9 Feb 2023 00:11:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E4CE06B0074; Wed, 8 Feb 2023 19:11:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DFD2D6B0075; Wed, 8 Feb 2023 19:11:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC51C6B0078; Wed, 8 Feb 2023 19:11:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id BF3856B0074 for ; Wed, 8 Feb 2023 19:11:14 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 9BD2B80C74 for ; Thu, 9 Feb 2023 00:11:14 +0000 (UTC) X-FDA: 80445823668.05.FF903B3 Received: from mail-ed1-f54.google.com (mail-ed1-f54.google.com [209.85.208.54]) by imf30.hostedemail.com (Postfix) with ESMTP id BEA6880017 for ; Thu, 9 Feb 2023 00:11:11 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=T83OX4EG; spf=pass (imf30.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.208.54 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1675901471; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=dOTjgYcWhqkMuhNenPNI1XlMmaNHM0OOaClLZboB/Wg=; b=NliyiVVbZ/1OuIqa08OXJXRUzK89XDhGk3cx1wKWHPaGA+h1sCs118FZwxLKcTBQiY6VZq uMgG+YOYVgH/vrZW9ms2cGpUvBx+33CFba/Dx4jpv3m8tpH5ZW+uFJy6ti2B2+FAOVEP2N +y9CE9ZjdKgw9Ejp1InupzxeROqytXQ= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=T83OX4EG; spf=pass (imf30.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.208.54 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1675901471; a=rsa-sha256; cv=none; b=oJUkYvHO9Lex6CeFVHKW0pGbt03MY+kfI6jZgHSaW+JKwpCh3w7oX0ThfRydPuS/jyWelx cyxBE4tLjaLTpz8sQPa0AWxWz9THjRnZskf95rwcw+wIqlUEpumRUDxnBRS+VV675i/nZh TMnXBfxwrCqiHmQR6VKwSLqnWF3nSto= Received: by mail-ed1-f54.google.com with SMTP id h3so662673eda.5 for ; Wed, 08 Feb 2023 16:11:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=dOTjgYcWhqkMuhNenPNI1XlMmaNHM0OOaClLZboB/Wg=; b=T83OX4EGnLSsuZ/1Jmo85gnC4KAwJ/j8TzibjPSwXWVdj4nwI3zeuGIoCvSxp02BTW RshIZyAY861CFrHXzK77FTX2kzrdkwR/vluOLyHkxzSFc8e5uPOyFK9yYRoGtWEbox4s A6gZ1ghgDQCpqgGLg/3FKJZyq64z4RE7lCTqPu9GS29CWM07AuPsk4/Zv94ySlXfgpx3 ytoKJiluVr90bcEo4hD/jynwQFykTla7UkQ0+iVm/rsMMElH9Wt7trRi+atzFnDPGTI3 gLpbBja79tGys+tPZf+E1Ew0ccBS+Bv1d4UrMtuT8Mb14xuuATLgA9DpiG/t05MSrffr EnnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=dOTjgYcWhqkMuhNenPNI1XlMmaNHM0OOaClLZboB/Wg=; b=Je2o06dL+IRApHvWqxXpyHtKcp1EO1YpyzjJKTbzke6ACtDJL2JA56CxAUdMny39bj 7sMZPnx9rikXTdcobEfxH35fbxw7Z9eNkt/5tJeyP25fJb9tz4EnvQHVkgI5YMa/w2Ii 6XphpQmmpIcXs1CY/7yMae83JNbwTE24QSzVeHKv8r26oglAi927JrV26XXyNLnwseYN 1aSXelrJ8oLzqbRtaEsec4xox8stA4aZFVbVth8ePGUXoqU/w0SME99+BCdcEzfNgFvK tTw6uq3pLqoJXvyuoNI+xSZ3hde5UYxDpU/QiskJ157gz9fVUyUhchbCZ5EAmAvYHLW7 49tA== X-Gm-Message-State: AO0yUKUaiBkDNhRdZLZBQjSPwCRryJ+mKB1lHN8mea3W+l73G0ZGEIWn o1EYXIVT2a8WJ0nV3T2Geoqv1A2DJEH9H8vMWTc= X-Google-Smtp-Source: AK7set8WGUS985JMz7z6vFLrlEJRzZJTSTm0/SygyG7AOs5OLC2GbWPDFFSscHF6uKvNYoysgu3zyt3I2z9+U9IhvvA= X-Received: by 2002:a50:d717:0:b0:4aa:a4e6:b323 with SMTP id t23-20020a50d717000000b004aaa4e6b323mr2388298edi.34.1675901470226; Wed, 08 Feb 2023 16:11:10 -0800 (PST) MIME-Version: 1.0 References: <20211120112738.45980-1-laoar.shao@gmail.com> <20211120112738.45980-8-laoar.shao@gmail.com> In-Reply-To: From: Alexei Starovoitov Date: Wed, 8 Feb 2023 16:10:59 -0800 Message-ID: Subject: Re: [PATCH v2 7/7] tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN To: John Stultz Cc: Yafang Shao , Andrew Morton , Network Development , bpf , "linux-perf-use." , Linux-Fsdevel , linux-mm , LKML , kernel test robot , kbuild test robot , Andrii Nakryiko , David Hildenbrand , Mathieu Desnoyers , Arnaldo Carvalho de Melo , Andrii Nakryiko , Michal Miroslaw , Peter Zijlstra , Steven Rostedt , Matthew Wilcox , Al Viro , Kees Cook , Petr Mladek , Kajetan Puchalski , Lukasz Luba , Qais Yousef , Daniele Di Proietto Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: BEA6880017 X-Stat-Signature: rmxuopnp6wfouxq78j1ndo7fayjzcukn X-Rspam-User: X-HE-Tag: 1675901471-588883 X-HE-Meta: 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 eh+QKhKj 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 D3bXX6bx fHmnZPRdt+3ouaprZzhO14GRFRInKw0WHG/exB7/arhxaWbhiB500nV71HVGVpKKM0/Ie/Wv/th39gnaZkpZYg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Feb 8, 2023 at 2:01 PM John Stultz wrote: > > On Sat, Nov 20, 2021 at 11:27:38AM +0000, Yafang Shao wrote: > > As the sched:sched_switch tracepoint args are derived from the kernel, > > we'd better make it same with the kernel. So the macro TASK_COMM_LEN is > > converted to type enum, then all the BPF programs can get it through BTF. > > > > The BPF program which wants to use TASK_COMM_LEN should include the header > > vmlinux.h. Regarding the test_stacktrace_map and test_tracepoint, as the > > type defined in linux/bpf.h are also defined in vmlinux.h, so we don't > > need to include linux/bpf.h again. > > > > Signed-off-by: Yafang Shao > > Acked-by: Andrii Nakryiko > > Acked-by: David Hildenbrand > > Cc: Mathieu Desnoyers > > Cc: Arnaldo Carvalho de Melo > > Cc: Andrii Nakryiko > > Cc: Michal Miroslaw > > Cc: Peter Zijlstra > > Cc: Steven Rostedt > > Cc: Matthew Wilcox > > Cc: David Hildenbrand > > Cc: Al Viro > > Cc: Kees Cook > > Cc: Petr Mladek > > --- > > include/linux/sched.h | 9 +++++++-- > > tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 6 +++--- > > tools/testing/selftests/bpf/progs/test_tracepoint.c | 6 +++--- > > 3 files changed, 13 insertions(+), 8 deletions(-) > > Hey all, > I know this is a little late, but I recently got a report that > this change was causiing older versions of perfetto to stop > working. > > Apparently newer versions of perfetto has worked around this > via the following changes: > https://android.googlesource.com/platform/external/perfetto/+/c717c93131b1b6e3705a11092a70ac47c78b731d%5E%21/ > https://android.googlesource.com/platform/external/perfetto/+/160a504ad5c91a227e55f84d3e5d3fe22af7c2bb%5E%21/ > > But for older versions of perfetto, reverting upstream commit > 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 > with TASK_COMM_LEN") is necessary to get it back to working. > > I haven't dug very far into the details, and obviously this doesn't > break with the updated perfetto, but from a high level this does > seem to be a breaking-userland regression. > > So I wanted to reach out to see if there was more context for this > breakage? I don't want to raise a unnecessary stink if this was > an unfortuante but forced situation. Let me understand what you're saying... The commit 3087c61ed2c4 did -/* Task command name length: */ -#define TASK_COMM_LEN 16 +/* + * Define the task command name length as enum, then it can be visible to + * BPF programs. + */ +enum { + TASK_COMM_LEN = 16, +}; and that caused: cat /sys/kernel/debug/tracing/events/task/task_newtask/format to print field:char comm[TASK_COMM_LEN]; offset:12; size:16; signed:0; instead of field:char comm[16]; offset:12; size:16; signed:0; so the ftrace parsing android tracing tool had to do: - if (Match(type_and_name.c_str(), R"(char [a-zA-Z_]+\[[0-9]+\])")) { + if (Match(type_and_name.c_str(), + R"(char [a-zA-Z_][a-zA-Z_0-9]*\[[a-zA-Z_0-9]+\])")) { to workaround this change. Right? And what are you proposing?