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=-0.3 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MIME_QP_LONG_LINE, SPF_HELO_NONE,SPF_PASS autolearn=no 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 17AE4C33C9E for ; Sat, 11 Jan 2020 07:57:38 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B657C206DA for ; Sat, 11 Jan 2020 07:57:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YvNIeLox" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B657C206DA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47vsdq44RFzDqgN for ; Sat, 11 Jan 2020 18:57:35 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::f42; helo=mail-qv1-xf42.google.com; envelope-from=arnaldo.melo@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=YvNIeLox; dkim-atps=neutral Received: from mail-qv1-xf42.google.com (mail-qv1-xf42.google.com [IPv6:2607:f8b0:4864:20::f42]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47vgqD1V1zzDqjV for ; Sat, 11 Jan 2020 11:35:03 +1100 (AEDT) Received: by mail-qv1-xf42.google.com with SMTP id l14so1638443qvu.12 for ; Fri, 10 Jan 2020 16:35:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:from:date:user-agent:in-reply-to:references:mime-version :content-transfer-encoding:subject:to:cc; bh=6ZxdMaOqxAtsCLY7Lzkx2L/EBnUsDnrBslrx0A7xKC4=; b=YvNIeLoxxUS8MiKp2Ri8iAcXzrJxtE44cmCaAzEOlIiO3zdIjAdic6y/7gp05iDy+4 Psa6obfkZ/2miGQ5CBZOM2hPQw13LKvkvkvxdObU65wzP3ra2LNlPLoI/PvksYjlJJGl iSS8P5cVN9p61Gb6Nps3ktzRFCv0Ing6Li0w3f+VU2FaDbtR+UbZqnBI7f57XL6zxiwV 8zc0GQwvgUDLz68MUfzUHbkOWN6RgoAeVP6n6Ni+2wDy9pXZ/Y5jKoEYEgnhpY8BItXX +vICW1PeMxcX+zNfgGRTBkMaN4NCrNgM0PyEOAUoMMz1lYO2qTltSh4Ch14nfdS6Qmzl zsBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:from:date:user-agent:in-reply-to :references:mime-version:content-transfer-encoding:subject:to:cc; bh=6ZxdMaOqxAtsCLY7Lzkx2L/EBnUsDnrBslrx0A7xKC4=; b=a4/tMzNrAPsLLRI7XjtTNFpoPte+gKlCu5RRv9g6rW6NF82GNfcIPaO66gpKc4h8fj bBvTm5ts+oBlSQsttVa3HKCiHFxWvk5cEpAVydb19e3ErWtTx1wxv+387EpH+Hl7l2RN ifceR+xj+96/MSQG+63jHQk3ikIqustM1qlwGOXpZcXxrLClf0VLFq6SWCJT/jXvLnQz XkPMbkiMODsc+GobPjANg6szh2qyXBLMAR6hOjAqSEkkAjcvdf8/0oYuIB8UlnvyXzvv 8yGQOuoOi8q4nOS+F1FM1pdr0OfOvFNokusVGc4QmHtU41ZsU4xJHV1Ow3AfxElloXm+ i/sg== X-Gm-Message-State: APjAAAUg38/Hgwv/B2KAA9NtEOn56zxHIB0tGgEQUD/mMnE/Mj20I1Zo GyMfwqNp5pZLjyZXd2sDrck= X-Google-Smtp-Source: APXvYqxPyWA8KpmKGMVMME8gPN1B98zu6uMFW1TJ+TYPsRSpYEPZl4k9D7BDYVrpcTXTD8zwqLuGjQ== X-Received: by 2002:a0c:f7c3:: with SMTP id f3mr1362344qvo.52.1578702900264; Fri, 10 Jan 2020 16:35:00 -0800 (PST) Received: from [192.168.86.249] ([179.97.37.151]) by smtp.gmail.com with ESMTPSA id z141sm1638958qkb.63.2020.01.10.16.34.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 10 Jan 2020 16:34:59 -0800 (PST) Message-ID: <5e191833.1c69fb81.8bc25.a88c@mx.google.com> From: arnaldo.melo@gmail.com Date: Fri, 10 Jan 2020 21:35:12 -0300 User-Agent: K-9 Mail for Android In-Reply-To: <2B79131A-3F76-47F5-AAB4-08BCA820473F@fb.com> References: <20200108160713.GI2844@hirez.programming.kicks-ass.net> <20200110140234.GO2844@hirez.programming.kicks-ass.net> <20200111005213.6dfd98fb36ace098004bde0e@kernel.org> <20200110164531.GA2598@kernel.org> <20200111084735.0ff01c758bfbfd0ae2e1f24e@kernel.org> <2B79131A-3F76-47F5-AAB4-08BCA820473F@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process To: Song Liu ,Masami Hiramatsu X-Mailman-Approved-At: Sat, 11 Jan 2020 18:51:38 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , "joonas.lahtinen@linux.intel.com" , Will Deacon , Alexei Starovoitov , Stephane Eranian , "james.bottomley@hansenpartnership.com" , Paul Mackerras , Jiri Olsa , Andi Kleen , Alexey Budankov , Igor Lubashev , James Morris , Alexander Shishkin , Ingo Molnar , Serge Hallyn , Robert Richter , "jani.nikula@linux.intel.com" , "rodrigo.vivi@intel.com" , Namhyung Kim , Kees@lists.ozlabs.org, Casey Schaufler Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" ,Jann Horn ,Thomas Gleixner ,Tvrtko Ursulin ,Lionel Landwerlin ,linux-kernel ,"linux-security-module@vger.kernel.org" ,"selinux@vger.kernel.org" ,"intel-gfx@lists.freedesktop.org" ,"bpf@vger.kernel.org" ,"linux-parisc@vger.kernel.org" ,"linuxppc-dev@lists.ozlabs.org" ,"linux-perf-users@vger.kernel.org" ,"linux-arm-kernel@lists.infradead.org" ,"oprofile-list@lists.sf.net" From: Arnaldo Carvalho de Melo Message-ID: On January 10, 2020 9:23:27 PM GMT-03:00, Song Liu wrote: > > >> On Jan 10, 2020, at 3:47 PM, Masami Hiramatsu >wrote: >>=20 >> On Fri, 10 Jan 2020 13:45:31 -0300 >> Arnaldo Carvalho de Melo wrote: >>=20 >>> Em Sat, Jan 11, 2020 at 12:52:13AM +0900, Masami Hiramatsu escreveu: >>>> On Fri, 10 Jan 2020 15:02:34 +0100 Peter Zijlstra > wrote: >>>>> Again, this only allows attaching to previously created kprobes, >it does >>>>> not allow creating kprobes, right? >>>=20 >>>>> That is; I don't think CAP_SYS_PERFMON should be allowed to create >>>>> kprobes=2E >>>=20 >>>>> As might be clear; I don't actually know what the user-ABI is for >>>>> creating kprobes=2E >>>=20 >>>> There are 2 ABIs nowadays, ftrace and ebpf=2E perf-probe uses ftrace >interface to >>>> define new kprobe events, and those events are treated as >completely same as >>>> tracepoint events=2E On the other hand, ebpf tries to define new >probe event >>>> via perf_event interface=2E Above one is that interface=2E IOW, it >creates new kprobe=2E >>>=20 >>> Masami, any plans to make 'perf probe' use the perf_event_open() >>> interface for creating kprobes/uprobes? >>=20 >> Would you mean perf probe to switch to perf_event_open()? >> No, perf probe is for setting up the ftrace probe events=2E I think we >can add an >> option to use perf_event_open()=2E But current kprobe creation from >perf_event_open() >> is separated from ftrace by design=2E > >I guess we can extend event parser to understand kprobe directly=2E >Instead of > > perf probe kernel_func > perf stat/record -e probe:kernel_func =2E=2E=2E > >We can just do=20 > > perf stat/record -e kprobe:kernel_func =2E=2E=2E You took the words from my mouth, exactly, that is a perfect use case, an = alternative to the 'perf probe' one of making a disabled event that then ge= ts activated via record/stat/trace, in many cases it's better, removes the = explicit probe setup case=2E Regards,=20 - Arnaldo > >Thanks, >Song