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authorArnaldo Carvalho de Melo <acme@redhat.com>2019-08-12 22:27:11 +0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-08-14 15:59:59 +0200
commit73e5de70dca00344cb48e018131a4cadec0fabf0 (patch)
tree49210714c5adf14b5495e1d3b33b6104b0543352 /tools/perf/builtin-ftrace.c
parentperf ftrace: Use CAP_SYS_ADMIN instead of euid==0 (diff)
downloadlinux-73e5de70dca00344cb48e018131a4cadec0fabf0.tar.xz
linux-73e5de70dca00344cb48e018131a4cadec0fabf0.zip
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@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Igor Lubashev <ilubashe@akamai.com> Cc: James Morris <jmorris@namei.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suzuki Poulouse <suzuki.poulose@arm.com> Link: https://lkml.kernel.org/n/tip-hhnbjdo8r67054of9zm2kxtl@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-ftrace.c')
-rw-r--r--tools/perf/builtin-ftrace.c8
1 files changed, 7 insertions, 1 deletions
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;
}