diff options
| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-05-12 15:44:55 -0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-05-12 15:44:55 -0300 |
| commit | 7d173913a6420f2818afeca70b268f064441f69b (patch) | |
| tree | 6f0113ffa465a23ffdd35acd7e60c9a8ba150cc4 | |
| parent | 106b816cb46ebd87408b4ed99a2e16203114daa6 (diff) | |
perf evsel: Improve EPERM error handling in open_strerror()
We were showing a hardcoded default value for the kernel.perf_event_paranoid
sysctl, now that it became more paranoid (1 -> 2 [1]), this would need to be
updated, instead show the current value:
[acme@jouet linux]$ perf record ls
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_SYS_ADMIN).
The current value is 2:
-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
[acme@jouet linux]$
[1] 0161028b7c8a ("perf/core: Change the default paranoia level to 2")
Reported-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-0gc4rdpg8d025r5not8s8028@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/evsel.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 738ce226002b..a5f339d447cc 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -2382,12 +2382,13 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target, "Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n" "which controls use of the performance events system by\n" "unprivileged users (without CAP_SYS_ADMIN).\n\n" - "The default value is 1:\n\n" + "The current value is %d:\n\n" " -1: Allow use of (almost) all events by all users\n" ">= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK\n" ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n" ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN", - target->system_wide ? "system-wide " : ""); + target->system_wide ? "system-wide " : "", + perf_event_paranoid()); case ENOENT: return scnprintf(msg, size, "The %s event is not supported.", perf_evsel__name(evsel)); |