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=-7.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 0DB29C47420 for ; Tue, 29 Sep 2020 16:06:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 955B1207F7 for ; Tue, 29 Sep 2020 16:06:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601395597; bh=17d99Pj6ycmLH+9l46C3/Edq052XmfsvQxsWb+F7NNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=X5D6s+Vbi9MHwxlEE2fWtJY9vLgRZ46IbO9AN9hiezchSDdXDI/+elUBxdAzHE5Pb EYw3VmFefPYMeqvarfCVXxZnkJmyaJP7LCuBnOjvcShhnuJ5YtWeB4TCWyWE3QGegW OHMFfZnbXPC6GHbKTPaoGU0BTSooYXtT1dAFaHN4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729112AbgI2QGg (ORCPT ); Tue, 29 Sep 2020 12:06:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:54246 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728401AbgI2QGg (ORCPT ); Tue, 29 Sep 2020 12:06:36 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EAE3A2075E; Tue, 29 Sep 2020 16:06:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601395595; bh=17d99Pj6ycmLH+9l46C3/Edq052XmfsvQxsWb+F7NNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Kourp7UCKmdccjNehxnXxkmQ0/4dQBrnQoOL6667NR+fXDyby/Ll+FQhXbzvRsXBV D+3nr0Hm8/MyicnEJN5jXv1J5bmpm9WwwK4v3NIFI/DDXCHJ+uEjZrmEMwdhoLywQh WmtVy5OrJk6Tu7wtYZap1ZEvce6lH3pZDxZCZLsg= Date: Tue, 29 Sep 2020 12:06:33 -0400 From: Sasha Levin To: Greg Kroah-Hartman Cc: Naresh Kamboju , linux- stable , Arnaldo Carvalho de Melo , open list , Stephane Eranian , Ian Rogers , Jiri Olsa , Alexander Shishkin , Mark Rutland , Namhyung Kim , Peter Zijlstra Subject: Re: [PATCH 4.19 146/245] perf stat: Force error in fallback on :k events Message-ID: <20200929160633.GA2415204@sasha-vm> References: <20200929105946.978650816@linuxfoundation.org> <20200929105954.090876288@linuxfoundation.org> <20200929142717.GB1203131@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200929142717.GB1203131@kroah.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 29, 2020 at 04:27:17PM +0200, Greg Kroah-Hartman wrote: >On Tue, Sep 29, 2020 at 07:03:46PM +0530, Naresh Kamboju wrote: >> On Tue, 29 Sep 2020 at 17:54, Greg Kroah-Hartman >> wrote: >> > >> > From: Stephane Eranian >> > >> > [ Upstream commit bec49a9e05db3dbdca696fa07c62c52638fb6371 ] >> > >> > When it is not possible for a non-privilege perf command to monitor at >> > the kernel level (:k), the fallback code forces a :u. That works if the >> > event was previously monitoring both levels. But if the event was >> > already constrained to kernel only, then it does not make sense to >> > restrict it to user only. >> > >> > Given the code works by exclusion, a kernel only event would have: >> > >> > attr->exclude_user = 1 >> > >> > The fallback code would add: >> > >> > attr->exclude_kernel = 1 >> > >> > In the end the end would not monitor in either the user level or kernel >> > level. In other words, it would count nothing. >> > >> > An event programmed to monitor kernel only cannot be switched to user >> > only without seriously warning the user. >> > >> > This patch forces an error in this case to make it clear the request >> > cannot really be satisfied. >> > >> > Behavior with paranoid 1: >> > >> > $ sudo bash -c "echo 1 > /proc/sys/kernel/perf_event_paranoid" >> > $ perf stat -e cycles:k sleep 1 >> > >> > Performance counter stats for 'sleep 1': >> > >> > 1,520,413 cycles:k >> > >> > 1.002361664 seconds time elapsed >> > >> > 0.002480000 seconds user >> > 0.000000000 seconds sys >> > >> > Old behavior with paranoid 2: >> > >> > $ sudo bash -c "echo 2 > /proc/sys/kernel/perf_event_paranoid" >> > $ perf stat -e cycles:k sleep 1 >> > Performance counter stats for 'sleep 1': >> > >> > 0 cycles:ku >> > >> > 1.002358127 seconds time elapsed >> > >> > 0.002384000 seconds user >> > 0.000000000 seconds sys >> > >> > New behavior with paranoid 2: >> > >> > $ sudo bash -c "echo 2 > /proc/sys/kernel/perf_event_paranoid" >> > $ perf stat -e cycles:k sleep 1 >> > Error: >> > You may not have permission to collect stats. >> > >> > Consider tweaking /proc/sys/kernel/perf_event_paranoid, >> > which controls use of the performance events system by >> > unprivileged users (without CAP_PERFMON or CAP_SYS_ADMIN). >> > >> > The current value is 2: >> > >> > -1: Allow use of (almost) all events by all users >> > Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK >> > >= 0: Disallow ftrace function tracepoint by users without CAP_PERFMON or CAP_SYS_ADMIN >> > Disallow raw tracepoint access by users without CAP_SYS_PERFMON or CAP_SYS_ADMIN >> > >= 1: Disallow CPU event access by users without CAP_PERFMON or CAP_SYS_ADMIN >> > >= 2: Disallow kernel profiling by users without CAP_PERFMON or CAP_SYS_ADMIN >> > >> > To make this setting permanent, edit /etc/sysctl.conf too, e.g.: >> > >> > kernel.perf_event_paranoid = -1 >> > >> > v2 of this patch addresses the review feedback from jolsa@redhat.com. >> > >> > Signed-off-by: Stephane Eranian >> > Reviewed-by: Ian Rogers >> > Acked-by: Jiri Olsa >> > Tested-by: Arnaldo Carvalho de Melo >> > Cc: Alexander Shishkin >> > Cc: Jiri Olsa >> > Cc: Mark Rutland >> > Cc: Namhyung Kim >> > Cc: Peter Zijlstra >> > Link: http://lore.kernel.org/lkml/20200414161550.225588-1-irogers@google.com >> > Signed-off-by: Arnaldo Carvalho de Melo >> > Signed-off-by: Sasha Levin >> >> perf failed on stable rc branch 4.19 on all devices. >> >> Reported-by: Naresh Kamboju >> >> build warning and errors, >> ----------------------------------- >> In file included from util/evlist.h:15:0, >> from util/evsel.c:30: >> util/evsel.c: In function 'perf_evsel__exit': >> util/util.h:25:28: warning: passing argument 1 of 'free' discards >> 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] >> #define zfree(ptr) ({ free(*ptr); *ptr = NULL; }) >> ^ >> util/evsel.c:1293:2: note: in expansion of macro 'zfree' >> zfree(&evsel->pmu_name); >> ^~~~~ >> In file included from >> /srv/oe/build/tmp-lkft-glibc/work/intel_corei7_64-linaro-linux/perf/1.0-r9/perf-1.0/tools/perf/arch/x86/include/perf_regs.h:5:0, >> from util/perf_regs.h:27, >> from util/event.h:11, >> from util/callchain.h:8, >> from util/evsel.c:26: >> perf/1.0-r9/recipe-sysroot/usr/include/stdlib.h:563:13: note: expected >> 'void *' but argument is of type 'const char *' >> extern void free (void *__ptr) __THROW; >> ^~~~ >> util/evsel.c: In function 'perf_evsel__fallback': >> util/evsel.c:2802:14: error: 'struct perf_evsel' has no member named >> 'core'; did you mean 'node'? >> if (evsel->core.attr.exclude_user) >> ^~~~ >> node > >I thought Sasha had dropped all of the offending patches. I'll go drop >this one and push out a new 4.19-rc release. I did, looks like this a new report. >But note, the latest 4.19.y tree doesn't even build perf for me, so I >can't really check this locally :( Same here. Naresh, does perf builds "out of the box" for you, or do you carry any patches on top? -- Thanks, Sasha