diff options
| author | Daniel Bristot de Oliveira <bristot@redhat.com> | 2021-06-29 19:10:26 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-06-29 16:37:50 -0400 |
| commit | 19c3eaa72288ce161441dd6b74b765a094d73488 (patch) | |
| tree | 1aa3dad24893fa906cbca4b021e14d29ef8d9251 /kernel/trace | |
| parent | 9913d5745bd720c4266805c8d29952a3702e4eca (diff) | |
trace/osnoise: Make 'noise' variable s64 in run_osnoise()
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.
Link: https://lkml.kernel.org/r/acd7cd6e7d56b798a298c3bc8139a390b3c4ab52.1624986368.git.bristot@redhat.com
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>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 5 |
1 files 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; /* |