From: Arnaldo Carvalho de Melo <acme@kernel•org>
To: Ingo Molnar <mingo@kernel•org>, Thomas Gleixner <tglx@linutronix•de>
Cc: Arnaldo Carvalho de Melo <acme@redhat•com>,
Mathieu Poirier <mathieu.poirier@linaro•org>,
Suzuki Poulouse <suzuki.poulose@arm•com>,
Clark Williams <williams@redhat•com>,
Alexey Budankov <alexey.budankov@linux•intel.com>,
Igor Lubashev <ilubashe@akamai•com>,
linux-kernel@vger•kernel.org, James Morris <jmorris@namei•org>,
linux-perf-users@vger•kernel.org,
Alexander Shishkin <alexander.shishkin@linux•intel.com>,
Peter Zijlstra <peterz@infradead•org>,
Jiri Olsa <jolsa@kernel•org>, Namhyung Kim <namhyung@kernel•org>,
linux-arm-kernel@lists•infradead.org
Subject: [PATCH 06/37] perf tools: Warn that perf_event_paranoid can restrict kernel symbols
Date: Thu, 29 Aug 2019 11:38:46 -0300 [thread overview]
Message-ID: <20190829143917.29745-7-acme@kernel.org> (raw)
In-Reply-To: <20190829143917.29745-1-acme@kernel.org>
From: Igor Lubashev <ilubashe@akamai•com>
Warn that /proc/sys/kernel/perf_event_paranoid can also restrict kernel
symbols.
Signed-off-by: Igor Lubashev <ilubashe@akamai•com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro•org>
Cc: Alexander Shishkin <alexander.shishkin@linux•intel.com>
Cc: Alexey Budankov <alexey.budankov@linux•intel.com>
Cc: James Morris <jmorris@namei•org>
Cc: Jiri Olsa <jolsa@kernel•org>
Cc: Namhyung Kim <namhyung@kernel•org>
Cc: Peter Zijlstra <peterz@infradead•org>
Cc: Suzuki Poulouse <suzuki.poulose@arm•com>
Cc: linux-arm-kernel@lists•infradead.org
Link: http://lkml.kernel.org/r/1566869956-7154-6-git-send-email-ilubashe@akamai.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat•com>
---
tools/perf/builtin-record.c | 2 +-
tools/perf/builtin-top.c | 2 +-
tools/perf/builtin-trace.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 359bb8f33e57..afe558449677 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -2372,7 +2372,7 @@ int cmd_record(int argc, const char **argv)
if (symbol_conf.kptr_restrict && !perf_evlist__exclude_kernel(rec->evlist))
pr_warning(
"WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted,\n"
-"check /proc/sys/kernel/kptr_restrict.\n\n"
+"check /proc/sys/kernel/kptr_restrict and /proc/sys/kernel/perf_event_paranoid.\n\n"
"Samples in kernel functions may not be resolved if a suitable vmlinux\n"
"file is not found in the buildid cache or in the vmlinux path.\n\n"
"Samples in kernel modules won't be resolved at all.\n\n"
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 5970723cd55a..29e910fb2d9a 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -770,7 +770,7 @@ static void perf_event__process_sample(struct perf_tool *tool,
if (!perf_evlist__exclude_kernel(top->session->evlist)) {
ui__warning(
"Kernel address maps (/proc/{kallsyms,modules}) are restricted.\n\n"
-"Check /proc/sys/kernel/kptr_restrict.\n\n"
+"Check /proc/sys/kernel/kptr_restrict and /proc/sys/kernel/perf_event_paranoid.\n\n"
"Kernel%s samples will not be resolved.\n",
al.map && map__has_symbols(al.map) ?
" modules" : "");
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 8ea62fd2591d..58a75dd3a571 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1382,7 +1382,7 @@ static char *trace__machine__resolve_kernel_addr(void *vmachine, unsigned long l
if (symbol_conf.kptr_restrict) {
pr_warning("Kernel address maps (/proc/{kallsyms,modules}) are restricted.\n\n"
- "Check /proc/sys/kernel/kptr_restrict.\n\n"
+ "Check /proc/sys/kernel/kptr_restrict and /proc/sys/kernel/perf_event_paranoid.\n\n"
"Kernel samples will not be resolved.\n");
machine->kptr_restrict_warned = true;
return NULL;
--
2.21.0
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prev parent reply other threads:[~2019-08-29 14:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190829143917.29745-1-acme@kernel.org>
2019-08-29 14:38 ` [PATCH 02/37] perf event: Check ref_reloc_sym before using it Arnaldo Carvalho de Melo
2019-08-29 14:38 ` [PATCH 03/37] perf tools: Use CAP_SYS_ADMIN with perf_event_paranoid checks Arnaldo Carvalho de Melo
2019-08-29 14:38 ` [PATCH 04/37] perf evsel: Kernel profiling is disallowed only when perf_event_paranoid > 1 Arnaldo Carvalho de Melo
2019-08-29 14:38 ` [PATCH 05/37] perf symbols: Use CAP_SYSLOG with kptr_restrict checks Arnaldo Carvalho de Melo
2019-08-29 14:38 ` Arnaldo Carvalho de Melo [this message]
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