From: "Steven Rostedt (VMware)" rostedt@goodmis.org
[ Upstream commit ee666a185558ac9a929e53b902a568442ed62416 ]
If tracing is disabled for some reason (traceoff_on_warning, command line, etc), the ftrace selftests are guaranteed to fail, as their results are defined by trace data in the ring buffers. If the ring buffers are turned off, the tests will fail, due to lack of data.
Because tracing being disabled is for a specific reason (warning, user decided to, etc), it does not make sense to enable tracing to run the self tests, as the test output may corrupt the reason for the tracing to be disabled.
Instead, simply skip the self tests and report that they are being skipped due to tracing being disabled.
Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b5815a022ecc..4b6df07d6dc6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1932,6 +1932,12 @@ static int run_tracer_selftest(struct tracer *type) if (!selftests_can_run) return save_selftest(type);
+ if (!tracing_is_on()) { + pr_warn("Selftest for tracer %s skipped due to tracing disabled\n", + type->name); + return 0; + } + /* * Run a selftest on this tracer. * Here we reset the trace buffer, and set the current