When linux is built without support for function graph tracer, the ftrace builtin of perf will fail when trying to reset max_graph_depth because the file does not exist. This prevents the use of function tracer from perf.
Do not attempt to write this file when the tracer in use is not function_graph. Signed-off-by: Julien Thierry <[email protected]> Cc: Will Deacon <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: [email protected] --- tools/perf/builtin-ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 25a42ac..48120f2 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) if (reset_tracing_cpu() < 0) return -1; - if (write_tracing_file("max_graph_depth", "0") < 0) + if (!strcmp(ftrace->tracer, "function_graph") && + write_tracing_file("max_graph_depth", "0") < 0) return -1; reset_tracing_filters(); -- 1.9.1
