[PATCH 1/2] trace/osnoise: Make 'noise' variable s64 in run_osnoise()

[PATCH 1/2] trace/osnoise: Make 'noise' variable s64 in run_osnoise()

[Daniel Bristot de Oliveira]

Dab Carpenter reported that:

 The patch bce29ac9ce0b: "trace: Add osnoise tracer" from Jun 22,
 2021, leads to the following static checker warning:

	kernel/trace/trace_osnoise.c:1103 run_osnoise()
	warn: unsigned 'noise' is never less than zero.

In this part of the code:

  1100                  /*
  1101                   * This shouldn't happen.
  1102                   */
  1103                  if (noise < 0) {
                            ^^^^^^^^^
  1104                          osnoise_taint("negative noise!");
  1105                          goto out;
  1106                  }
  1107

And the static checker is right because 'noise' is u64.

Make noise s64 and keep the check. It is important to check if
the time read is behaving correctly - so we can trust the results.

I also re-arranged some variable declarations.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-kernel@vger.kernel.org
Fixes: bce29ac9ce0b ("trace: Add osnoise tracer")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
---
 kernel/trace/trace_osnoise.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 085a83de98ad..cc1faca1a620 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -1042,15 +1042,16 @@ static void osnoise_stop_tracing(void)
 static int run_osnoise(void)
 {
 	struct osnoise_variables *osn_var = this_cpu_osn_var();
-	u64 noise = 0, sum_noise = 0, max_noise = 0;
 	struct trace_array *tr = osnoise_trace;
 	u64 start, sample, last_sample;
 	u64 last_int_count, int_count;
+	s64 noise = 0, max_noise = 0;
 	s64 total, last_total = 0;
 	struct osnoise_sample s;
 	unsigned int threshold;
-	int hw_count = 0;
 	u64 runtime, stop_in;
+	u64 sum_noise = 0;
+	int hw_count = 0;
 	int ret = -1;
 
 	/*
-- 
2.31.1

[PATCH 2/2] trace/timerlat: Fix indentation on timerlat_main()

[Daniel Bristot de Oliveira]

Dan Carpenter reported that:

 The patch a955d7eac177: "trace: Add timerlat tracer" from Jun 22,
 2021, leads to the following static checker warning:

	kernel/trace/trace_osnoise.c:1400 timerlat_main()
	warn: inconsistent indenting

here:
  1389          while (!kthread_should_stop()) {
  1390                  now = ktime_to_ns(hrtimer_cb_get_time(&tlat->timer));
  1391                  diff = now - tlat->abs_period;
  1392
  1393                  s.seqnum = tlat->count;
  1394                  s.timer_latency = diff;
  1395                  s.context = THREAD_CONTEXT;
  1396
  1397                  trace_timerlat_sample(&s);
  1398
  1399  #ifdef CONFIG_STACKTRACE
  1400          if (osnoise_data.print_stack)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	    This should be indented another tab?

  1401                  if (osnoise_data.print_stack <= time_to_us(diff))
  1402                          timerlat_dump_stack();
  1403  #endif /* CONFIG_STACKTRACE */
  1404
  1405                  tlat->tracing_thread = false;
  1406                  if (osnoise_data.stop_tracing_total)
  1407                          if (time_to_us(diff) >= osnoise_data.stop_tracing_total)
  1408                                  osnoise_stop_tracing();
  1409
  1410                  wait_next_period(tlat);
  1411          }

And the static checker is right. Fix the indentation.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-kernel@vger.kernel.org
Fixes: a955d7eac177 ("trace: Add timerlat tracer")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
---
 kernel/trace/trace_osnoise.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index cc1faca1a620..a7e3c24dee13 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -1403,9 +1403,9 @@ static int timerlat_main(void *data)
 		trace_timerlat_sample(&s);
 
 #ifdef CONFIG_STACKTRACE
-	if (osnoise_data.print_stack)
-		if (osnoise_data.print_stack <= time_to_us(diff))
-			timerlat_dump_stack();
+		if (osnoise_data.print_stack)
+			if (osnoise_data.print_stack <= time_to_us(diff))
+				timerlat_dump_stack();
 #endif /* CONFIG_STACKTRACE */
 
 		tlat->tracing_thread = false;
-- 
2.31.1