ftrace: irqsoff use raw_smp_processor_id
This patch changes the use of __get_cpu_var to explicitly calling
raw_smp_processor_id and using the per_cpu() macro. On some debug
configurations, the use of __get_cpu_var may cause ftrace to trigger
and this can cause problems with the irqsoff tracing.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index d0c1748..761f3ec 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -204,14 +204,14 @@
if (likely(!tracer_enabled))
return;
- if (__get_cpu_var(tracing_cpu))
+ cpu = raw_smp_processor_id();
+
+ if (per_cpu(tracing_cpu, cpu))
return;
- cpu = raw_smp_processor_id();
data = tr->data[cpu];
- if (unlikely(!data) || unlikely(!head_page(data)) ||
- atomic_read(&data->disabled))
+ if (unlikely(!data) || atomic_read(&data->disabled))
return;
atomic_inc(&data->disabled);
@@ -225,7 +225,7 @@
trace_function(tr, data, ip, parent_ip, flags);
- __get_cpu_var(tracing_cpu) = 1;
+ per_cpu(tracing_cpu, cpu) = 1;
atomic_dec(&data->disabled);
}
@@ -238,16 +238,16 @@
struct trace_array_cpu *data;
unsigned long flags;
+ cpu = raw_smp_processor_id();
/* Always clear the tracing cpu on stopping the trace */
- if (unlikely(__get_cpu_var(tracing_cpu)))
- __get_cpu_var(tracing_cpu) = 0;
+ if (unlikely(per_cpu(tracing_cpu, cpu)))
+ per_cpu(tracing_cpu, cpu) = 0;
else
return;
if (!tracer_enabled)
return;
- cpu = raw_smp_processor_id();
data = tr->data[cpu];
if (unlikely(!data) || unlikely(!head_page(data)) ||
@@ -255,6 +255,7 @@
return;
atomic_inc(&data->disabled);
+
local_save_flags(flags);
trace_function(tr, data, ip, parent_ip, flags);
check_critical_timing(tr, data, parent_ip ? : ip, cpu);
@@ -376,7 +377,7 @@
static void __irqsoff_tracer_init(struct trace_array *tr)
{
irqsoff_trace = tr;
- /* make sure that the tracer is visibel */
+ /* make sure that the tracer is visible */
smp_wmb();
if (tr->ctrl)