Merge branches 'tracing/blktrace', 'tracing/ftrace' and 'tracing/urgent' into tracing...

[pandora-kernel.git] / kernel / trace / trace_selftest.c

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 0c9aa14..7238646 100644 (file)
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -24,10 +24,20 @@ static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
 {
        struct ring_buffer_event *event;
        struct trace_entry *entry;
+       unsigned int loops = 0;
 
        while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
                entry = ring_buffer_event_data(event);
 
+               /*
+                * The ring buffer is a size of trace_buf_size, if
+                * we loop more than the size, there's something wrong
+                * with the ring buffer.
+                */
+               if (loops++ > trace_buf_size) {
+                       printk(KERN_CONT ".. bad ring buffer ");
+                       goto failed;
+               }
                if (!trace_valid_entry(entry)) {
                        printk(KERN_CONT ".. invalid entry %d ",
                                entry->type);
@@ -58,11 +68,20 @@ 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);
 
@@ -107,9 +126,9 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
        func();
 
        /*
-        * Some archs *cough*PowerPC*cough* add charachters to the
+        * Some archs *cough*PowerPC*cough* add characters to the
         * start of the function names. We simply put a '*' to
-        * accomodate them.
+        * accommodate them.
         */
        func_name = "*" STR(DYN_FTRACE_TEST_NAME);
 
@@ -622,7 +641,7 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
        ret = tracer_init(trace, tr);
        if (ret) {
                warn_failed_init_tracer(trace, ret);
-               return 0;
+               return ret;
        }
 
        /* Sleep for a 1/10 of a second */
@@ -634,6 +653,11 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
        trace->reset(tr);
        tracing_start();
 
+       if (!ret && !count) {
+               printk(KERN_CONT ".. no entries found ..");
+               ret = -1;
+       }
+
        return ret;
 }
 #endif /* CONFIG_SYSPROF_TRACER */
@@ -661,6 +685,11 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
        trace->reset(tr);
        tracing_start();
 
+       if (!ret && !count) {
+               printk(KERN_CONT ".. no entries found ..");
+               ret = -1;
+       }
+
        return ret;
 }
 #endif /* CONFIG_BRANCH_TRACER */