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tracing: make tracing_reset safe for external use

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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>
This commit is contained in:
Steven Rostedt 2009-09-04 12:35:16 -04:00 committed by Steven Rostedt
parent 2f26ebd549
commit f633903af2
1 changed files with 15 additions and 2 deletions
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17
kernel/trace/trace.c
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@ -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);
}