tracing: make tracing_reset safe for external use (f633903a) · Commits · 戴 / test

Reseting the trace buffer without first disabling the buffer and waiting for any writers to complete, can corrupt the ring buffer. This patch makes the external version of tracing_reset safe from corruption by disabling the ring buffer and calling synchronize_sched. This version can no longer be called from interrupt context. But all those callers have been removed. Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

+15 −2

Original line number	Diff line number	Diff line
		@@ -641,13 +641,26 @@ void unregister_tracer(struct tracer *type)
		mutex_unlock(&trace_types_lock);
		}

		void tracing_reset(struct trace_array *tr, int cpu)
		static void __tracing_reset(struct trace_array *tr, int cpu)
		{
		ftrace_disable_cpu();
		ring_buffer_reset_cpu(tr->buffer, cpu);
		ftrace_enable_cpu();
		}

		void tracing_reset(struct trace_array *tr, int cpu)
		{
		struct ring_buffer *buffer = tr->buffer;

		ring_buffer_record_disable(buffer);

		/* Make sure all commits have finished */
		synchronize_sched();
		__tracing_reset(tr, cpu);

		ring_buffer_record_enable(buffer);
		}

		void tracing_reset_online_cpus(struct trace_array *tr)
		{
		struct ring_buffer *buffer = tr->buffer;
		@@ -661,7 +674,7 @@ void tracing_reset_online_cpus(struct trace_array *tr)
		tr->time_start = ftrace_now(tr->cpu);

		for_each_online_cpu(cpu)
		tracing_reset(tr, cpu);
		__tracing_reset(tr, cpu);

		ring_buffer_record_enable(buffer);
		}

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