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authorDaniel Bristot de Oliveira2021-06-29 19:10:26 +0200
committerSteven Rostedt (VMware)2021-06-29 16:37:50 -0400
commit19c3eaa72288ce161441dd6b74b765a094d73488 (patch)
tree1aa3dad24893fa906cbca4b021e14d29ef8d9251 /kernel
parent9913d5745bd720c4266805c8d29952a3702e4eca (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')
-rw-r--r--kernel/trace/trace_osnoise.c5
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;
/*