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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 96CBEC4741F for ; Tue, 29 Sep 2020 14:27:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 404D82074F for ; Tue, 29 Sep 2020 14:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601389634; bh=N22FwIdH98oW9vtKFTALgnJGDqMt/w7VFFG1kFRSiAY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=CKf1nM3Lh/rycvI8ts/B+WMUR/r+3QF+Xfz5VOxd3g46CC0cqTy7z9FCtIh1k0cn7 PbWP7PI/L/yyuKPBm/ejUqfYw+JOTfwiMli8l/fnt0Lg0MSSuOKFRmBGQSHbC2QMys LD+ik47+oJFzrkqI1XHSvJecyKRuKRzAFvnHW2N0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729117AbgI2O1N (ORCPT ); Tue, 29 Sep 2020 10:27:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:39484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727543AbgI2O1N (ORCPT ); Tue, 29 Sep 2020 10:27:13 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 276C220739; Tue, 29 Sep 2020 14:27:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601389631; bh=N22FwIdH98oW9vtKFTALgnJGDqMt/w7VFFG1kFRSiAY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NQb0lKqG2f8od92Iaa7rEiYe9W0Rr2XtetonmHgbG+COIsTqiayRP4KOpv6xAXgwk 22ax2NH7fETrDC4Jfb+jOWd/meTqThQLMiijTA9PEkP+REU8iwsbaCXmSdE5jRvKMV bsxSVZQYdhnX7FUI4rzQp3G3dgIBKSGjHYOtwgeA= Date: Tue, 29 Sep 2020 16:27:17 +0200 From: Greg Kroah-Hartman To: Naresh Kamboju Cc: linux- stable , Arnaldo Carvalho de Melo , open list , Stephane Eranian , Ian Rogers , Jiri Olsa , Alexander Shishkin , Mark Rutland , Namhyung Kim , Peter Zijlstra , Sasha Levin Subject: Re: [PATCH 4.19 146/245] perf stat: Force error in fallback on :k events Message-ID: <20200929142717.GB1203131@kroah.com> References: <20200929105946.978650816@linuxfoundation.org> <20200929105954.090876288@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. But note, the latest 4.19.y tree doesn't even build perf for me, so I can't really check this locally :( thanks, greg k-h