Commit-ID: 73e5de70dca00344cb48e018131a4cadec0fabf0
Gitweb: https://git.kernel.org/tip/73e5de70dca00344cb48e018131a4cadec0fabf0
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Mon, 12 Aug 2019 17:27:11 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 14 Aug 2019 10:59:59 -0300
perf ftrace: Improve error message about capability to use ftrace
If we link against libcap, then we can state that CAP_SYS_ADMIN is
needed, if not, fallback to telling the user it needs to be root, as was
before linking against libcap.
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
Cc: Igor Lubashev <ilubashe@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Suzuki Poulouse <suzuki.poulose@xxxxxxx>
Link: https://lkml.kernel.org/n/tip-hhnbjdo8r67054of9zm2kxtl@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-ftrace.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 01a5bb58eb04..1367bb5046a7 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -284,7 +284,13 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
};
if (!perf_cap__capable(CAP_SYS_ADMIN)) {
- pr_err("ftrace only works for root!\n");
+ pr_err("ftrace only works for %s!\n",
+#ifdef HAVE_LIBCAP_SUPPORT
+ "users with the SYS_ADMIN capability"
+#else
+ "root"
+#endif
+ );
return -1;
}
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