tracing: disable tracing while testing ring buffer
[linux-2.6.git] / kernel / trace / trace_selftest.c
index 88c8eb7..a7e0ef6 100644 (file)
@@ -57,11 +57,20 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
 
        cnt = ring_buffer_entries(tr->buffer);
 
+       /*
+        * The trace_test_buffer_cpu runs a while loop to consume all data.
+        * If the calling tracer is broken, and is constantly filling
+        * the buffer, this will run forever, and hard lock the box.
+        * We disable the ring buffer while we do this test to prevent
+        * a hard lock up.
+        */
+       tracing_off();
        for_each_possible_cpu(cpu) {
                ret = trace_test_buffer_cpu(tr, cpu);
                if (ret)
                        break;
        }
+       tracing_on();
        __raw_spin_unlock(&ftrace_max_lock);
        local_irq_restore(flags);