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From: Ben Hutchings <ben@decadent.org.uk>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH RESEND] perf: Document the perf sysctls
Date: Tue, 19 Jan 2016 21:35:15 +0000
Message-ID: <20160119213515.GG2637@decadent.org.uk> (raw)
In-Reply-To: <20160111151958.GQ28542@decadent.org.uk>


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perf_event_paranoid was only documented in source code and a perf
error message.  Move the documentation from the error message to
Documentation/sysctl/kernel.txt.

perf_cpu_time_max_percent was already documented but missing from the
list at the top, so add it there.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 Documentation/sysctl/kernel.txt | 13 +++++++++++++
 tools/perf/util/evsel.c         |  7 ++-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index af70d15..88a2c8e 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -58,6 +58,8 @@ show up in /proc/sys/kernel:
 - panic_on_stackoverflow
 - panic_on_unrecovered_nmi
 - panic_on_warn
+- perf_cpu_time_max_percent
+- perf_event_paranoid
 - pid_max
 - powersave-nap               [ PPC only ]
 - printk
@@ -624,6 +626,17 @@ allowed to execute.
 
 ==============================================================
 
+perf_event_paranoid:
+
+Controls use of the performance events system by unprivileged
+users (without CAP_SYS_ADMIN).  The default value is 1.
+
+ -1: Allow use of (almost) all events by all users
+>=0: Disallow raw tracepoint access by users without CAP_IOC_LOCK
+>=1: Disallow CPU event access by users without CAP_SYS_ADMIN
+>=2: Disallow kernel profiling by users without CAP_SYS_ADMIN
+
+==============================================================
 
 pid_max:
 
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 397fb4e..9b4df11 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2314,11 +2314,8 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
 	case EACCES:
 		return scnprintf(msg, size,
 		 "You may not have permission to collect %sstats.\n"
-		 "Consider tweaking /proc/sys/kernel/perf_event_paranoid:\n"
-		 " -1 - Not paranoid at all\n"
-		 "  0 - Disallow raw tracepoint access for unpriv\n"
-		 "  1 - Disallow cpu events for unpriv\n"
-		 "  2 - Disallow kernel profiling for unpriv",
+		 "Consider tweaking /proc/sys/kernel/perf_event_paranoid -\n"
+		 "see Documentation/sysctl/kernel.txt",
 				 target->system_wide ? "system-wide " : "");
 	case ENOENT:
 		return scnprintf(msg, size, "The %s event is not supported.",


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  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-11 15:19 [PATCH 0/2] Document and extend kernel.perf_event_paranoid Ben Hutchings
2016-01-11 15:21 ` [PATCH 1/2] Documentation,perf: Document the perf sysctls Ben Hutchings
2016-01-11 15:23 ` [PATCH 2/2] security,perf: Allow further restriction of perf_event_open Ben Hutchings
2016-04-13 16:12   ` [kernel-hardening] " Kees Cook
2016-06-04 20:56     ` Jeffrey Vander Stoep
     [not found]     ` <CABXk95BE3wpgq-Y08G+Z3ZJbxJwgiuVvtQGaV4n-tD6GKNiFKg@mail.gmail.com>
2016-06-16 22:27       ` Kees Cook
2016-06-17  6:54         ` Peter Zijlstra
2016-06-17 16:16           ` Daniel Micay
2016-06-17 20:00             ` Arnaldo Carvalho de Melo
2016-06-18  0:51               ` Daniel Micay
2016-06-17  5:56   ` Alexander Shishkin
2016-06-17 12:18     ` Ben Hutchings
2016-06-17 15:24     ` [kernel-hardening] " Daniel Micay
2016-01-19 21:35 ` Ben Hutchings [this message]
2016-01-21 14:25   ` [PATCH RESEND] perf: Document the perf sysctls Arnaldo Carvalho de Melo
2016-02-03 10:08   ` [tip:perf/core] perf tools: " tip-bot for Ben Hutchings

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