[PATCH 19/23] perf ftrace: Move setup_pager before opening trace_pipe

Arnaldo Carvalho de Melo
2017-06-20T01:59:42Z

From: Namhyung Kim <namhyung@kernel.org>

The 'perf ftrace' command fails to reset tracer after finishing
recording like below:

$ sudo perf ftrace -v hello
write 'nop' to tracing/current_tracer failed: Device or resource busy
...

This is because the trace_pipe file is open in pager process. Move the
pager setup to before opening the file.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kernel-team@lge.com
Fixes: 583359646fde ("perf ftrace: Use pager for displaying result")
Link: http://lkml.kernel.org/r/20170618142302.25390-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-ftrace.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 966a94fa8200..982b98ee639e 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -231,6 +231,8 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
goto out_reset;
}

+ setup_pager();
+
trace_file = get_tracing_file("trace_pipe");
if (!trace_file) {
pr_err("failed to open trace_pipe\n");
@@ -254,8 +256,6 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
goto out_close_fd;
}

- setup_pager();
-
perf_evlist__start_workload(ftrace->evlist);

while (!done) {
--
2.9.4