[PATCH AUTOSEL 5.3 079/203] perf ftrace: Use CAP_SYS_ADMIN instead of euid==0

[Sasha Levin]

From: Igor Lubashev <ilubashe@xxxxxxxxxx>

[ Upstream commit c766f3df635de14295e410c6dd5410bc416c24a0 ]

The kernel requires CAP_SYS_ADMIN instead of euid==0 to mount debugfs
for ftrace.  Make perf do the same.

Signed-off-by: Igor Lubashev <ilubashe@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Suzuki Poulouse <suzuki.poulose@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/bd8763b72ed4d58d0b42d44fbc7eb474d32e53a3.1565188228.git.ilubashe@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 tools/perf/builtin-ftrace.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 0193128104056..10971255fd2dc 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -13,6 +13,7 @@
 #include <signal.h>
 #include <fcntl.h>
 #include <poll.h>
+#include <linux/capability.h>
 
 #include "debug.h"
 #include <subcmd/parse-options.h>
@@ -21,6 +22,7 @@
 #include "target.h"
 #include "cpumap.h"
 #include "thread_map.h"
+#include "util/cap.h"
 #include "util/config.h"
 
 
@@ -281,7 +283,7 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 		.events = POLLIN,
 	};
 
-	if (geteuid() != 0) {
+	if (!perf_cap__capable(CAP_SYS_ADMIN)) {
 		pr_err("ftrace only works for root!\n");
 		return -1;
 	}
-- 
2.20.1