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-rw-r--r--kernel/trace/trace_selftest.c35
1 files changed, 32 insertions, 3 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 0c9aa1457e5..7238646b872 100644
--- 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 */