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Tue, 07 Apr 2020 10:02:53 -0700 (PDT) Received: from quaco.ghostprotocols.net ([179.97.37.151]) by smtp.gmail.com with ESMTPSA id r40sm18041660qtc.39.2020.04.07.10.02.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Apr 2020 10:02:53 -0700 (PDT) From: Arnaldo Carvalho de Melo X-Google-Original-From: Arnaldo Carvalho de Melo Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 2B1C8409A3; Tue, 7 Apr 2020 14:02:51 -0300 (-03) Date: Tue, 7 Apr 2020 14:02:51 -0300 To: Alexey Budankov Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Alexei Starovoitov , Ingo Molnar , James Morris , Namhyung Kim , Serge Hallyn , Jiri Olsa , Song Liu , Andi Kleen , Stephane Eranian , Igor Lubashev , Thomas Gleixner , linux-kernel , "linux-security-module@vger.kernel.org" , "selinux@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , "linux-doc@vger.kernel.org" , linux-man@vger.kernel.org Subject: Re: [PATCH v8 00/12] Introduce CAP_PERFMON to secure system performance monitoring and observability Message-ID: <20200407170251.GE12003@kernel.org> References: <20200407143014.GD11186@kernel.org> <20200407143551.GF11186@kernel.org> <10cc74ee-8587-8cdb-f85f-5724b370a2ce@linux.intel.com> <20200407163654.GB12003@kernel.org> <85da1e42-2cf2-98ca-1e0c-2cf3469b7d30@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <85da1e42-2cf2-98ca-1e0c-2cf3469b7d30@linux.intel.com> X-Url: http://acmel.wordpress.com Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Em Tue, Apr 07, 2020 at 07:52:56PM +0300, Alexey Budankov escreveu: > > On 07.04.2020 19:36, Arnaldo Carvalho de Melo wrote: > > Em Tue, Apr 07, 2020 at 05:54:27PM +0300, Alexey Budankov escreveu: > >> Could makes sense adding cap_ipc_lock to the binary to isolate from this: > >> kernel/events/core.c: 6101 > >> if ((locked > lock_limit) && perf_is_paranoid() && > >> !capable(CAP_IPC_LOCK)) { > >> ret = -EPERM; > >> goto unlock; > >> } > > That did the trick, I'll update the documentation and include in my > > "Committer testing" section: > Looks like top mode somehow reaches perf mmap limit described here [1]. > Using -m option solves the issue avoiding cap_ipc_lock on my 8 cores machine: > perf top -e cycles -m 1 So this would read better? diff --git a/Documentation/admin-guide/perf-security.rst b/Documentation/admin-guide/perf-security.rst index ed33682e26b0..d44dd24b0244 100644 --- a/Documentation/admin-guide/perf-security.rst +++ b/Documentation/admin-guide/perf-security.rst @@ -127,8 +127,8 @@ taken to create such groups of privileged Perf users. :: - # setcap "cap_perfmon,cap_ipc_lock,cap_sys_ptrace,cap_syslog=ep" perf - # setcap -v "cap_perfmon,cap_ipc_lock,cap_sys_ptrace,cap_syslog=ep" perf + # setcap "cap_perfmon,cap_sys_ptrace,cap_syslog=ep" perf + # setcap -v "cap_perfmon,cap_sys_ptrace,cap_syslog=ep" perf perf: OK # getcap perf perf = cap_sys_ptrace,cap_syslog,cap_perfmon+ep @@ -140,6 +140,10 @@ i.e.: # setcap "38,cap_ipc_lock,cap_sys_ptrace,cap_syslog=ep" perf +Note that you may need to have 'cap_ipc_lock' in the mix for tools such as +'perf top', alternatively use 'perf top -m N', to reduce the memory that +it uses for the perf ring buffer, see the memory allocation section below. + As a result, members of perf_users group are capable of conducting performance monitoring and observability by using functionality of the configured Perf tool executable that, when executes, passes perf_events