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Commit c5f888ca authored by Steven Rostedt's avatar Steven Rostedt Committed by Thomas Gleixner
Browse files

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: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 4d9493c9

kernel/trace/trace_irqsoff.c

+10 −9
Original line number Diff line number Diff line
@@ -204,14 +204,14 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) 
	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 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) 


	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 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) 
	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 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) 
		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 stop_irqsoff_tracer(struct trace_array *tr) 
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)