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=-8.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 A14B5C433E2 for ; Tue, 8 Sep 2020 19:27:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 686C92078B for ; Tue, 8 Sep 2020 19:27:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ZEGSvO1X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732129AbgIHT1c (ORCPT ); Tue, 8 Sep 2020 15:27:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731053AbgIHT12 (ORCPT ); Tue, 8 Sep 2020 15:27:28 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34201C061755; Tue, 8 Sep 2020 12:27:27 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id g72so193175qke.8; Tue, 08 Sep 2020 12:27:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=EuLkSq/h0PySLcoqUIZc9Efa6tDdDoFulMc8JT2FysQ=; b=ZEGSvO1Xxpu4aYBEXdy/Uqc+1JVUorIAdGjltx0ruEgo5ZTtEgGP7I+4jiQA7N6ow2 +4Ilwq9NZX5LyYDKc1yKs0o1fk8JUVY43cFEU77WQvKnoSwLbJutwoATJASAqvV0Fof0 SxwgXE3ob7/3vdfQDXj+sSNo7We5M34zE3Sa0+/WN5i0XaK0xwXa7zUCc+ypiExINtpy ZjbU292Fb+cNMOU68F6UCgcOpqQj7ClVDPspjDSo7N3nDqUmfi2QtNb88OCDKaxXJ3wd ZBLphlojXQn4AzogWIsdd3DDaZGxk9JwYuz7qAj7r+T7AL1KIMFCvgbdpuJDSroD+XPt VHaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=EuLkSq/h0PySLcoqUIZc9Efa6tDdDoFulMc8JT2FysQ=; b=Oce3LMu0THjPqGfcUFj6HyhLwc9HR3SrSvyLtHyRuqxP0PhwsFBUhS2JVVpB2AtEJc mtAYqnc9A6F5AlOWdUJSqvyztJfweCLmvlOTvAPnDw99LCc82aEuoP7bdW0AeG9REejZ hRYKSavG8Q4hAkxFhppfz3gL8cPSLOolO5BjHVMjYrvWsItfByuO+gSsD5RloBXK9IUN VeIrU6wJJR234VIUMiQlqYa1mQScs3vgtKB9QJ+l0VFjXc5IEVdP3cQdRbf22nVZLFXu yWh2KFcqFwSHuOGG/quyor+O4Gd/6ZtZ2tt6/d+/yT3DZFTzwmqkLGV06tANACcp9bnv Xc7w== X-Gm-Message-State: AOAM530TXWXpsJfOIFq6CJhc5cbWu6Zl9tLr6OeQrVgrZloL/g/oyqeE Q45VnRF02IixxOTFYhdQ/ss= X-Google-Smtp-Source: ABdhPJyITvFLn0aDwyur1S830ay0M188rfil6lyR9M/2GxDZBgbKck1xnCqdKDMGjOSzwW7KdhPBVg== X-Received: by 2002:a37:e504:: with SMTP id e4mr134369qkg.290.1599593246277; Tue, 08 Sep 2020 12:27:26 -0700 (PDT) Received: from bpf-dev (pc-199-79-45-190.cm.vtr.net. [190.45.79.199]) by smtp.gmail.com with ESMTPSA id g45sm422689qtb.60.2020.09.08.12.27.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Sep 2020 12:27:25 -0700 (PDT) Date: Tue, 8 Sep 2020 16:27:20 -0300 From: Carlos Antonio Neira Bustos To: Andrii Nakryiko Cc: Networking , Yonghong Song , "Eric W. Biederman" , Jesper Dangaard Brouer , bpf , Andrii Nakryiko Subject: Re: [PATCH v1 bpf-next] bpf: new helper bpf_get_current_pcomm Message-ID: <20200908192719.GA1300@bpf-dev> References: <20200826160424.14131-1-cneirabustos@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Aug 26, 2020 at 10:25:55PM -0700, Andrii Nakryiko wrote: > On Wed, Aug 26, 2020 at 9:06 AM Carlos Neira wrote: > > > > In multi-threaded applications bpf_get_current_comm is returning per-thread > > names, this helper will return comm from real_parent. > > This makes a difference for some Java applications, where get_current_comm is > > returning per-thread names, but get_current_pcomm will return "java". > > > > Why not bpf_probe_read_kernel_str(dst, 16, task->real_parent->comm) > for fentry/fexit/tp_btf/etc BTF-aware BPF programs or > BPF_CORE_READ_STR_INTO(dst, task, real_parent, comm) for any BPF > program that has bpf_probe_read_kernel[_str]() (which is pretty much > every BPF program nowadays, I think)? > > Yes, CONFIG_DEBUG_INFO_BTF=y Kconfig is a requirement, but it's a good > idea to have that if you are using BPF anyways. > > > Signed-off-by: Carlos Neira > > --- > > include/linux/bpf.h | 1 + > > include/uapi/linux/bpf.h | 15 ++++- > > kernel/bpf/core.c | 1 + > > kernel/bpf/helpers.c | 28 +++++++++ > > kernel/trace/bpf_trace.c | 2 + > > tools/include/uapi/linux/bpf.h | 15 ++++- > > .../selftests/bpf/prog_tests/current_pcomm.c | 57 +++++++++++++++++++ > > .../selftests/bpf/progs/test_current_pcomm.c | 17 ++++++ > > 8 files changed, 134 insertions(+), 2 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/current_pcomm.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_current_pcomm.c > > > > [...] Thanks Andrii, I'll use bpf_probe_read_kernel_str(dst, 16, task->real_parent->comm), I was not aware of that. Bests!.