tracing: Clear all trace buffers when unloaded module event was used
Currently we do not know what buffer a module event was enabled in.
On unload, it is safest to clear all buffer instances, not just the
top level buffer.
Todo: Clear only the buffer that the event was used in. The
infrastructure is there to do this, but it makes the code a bit
more complex. Lets get the current code vetted before we add that.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 9a7dc4b..a376ab5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1649,14 +1649,18 @@
list_del(&file_ops->list);
kfree(file_ops);
}
+ up_write(&trace_event_mutex);
/*
* It is safest to reset the ring buffer if the module being unloaded
- * registered any events that were used.
+ * registered any events that were used. The only worry is if
+ * a new module gets loaded, and takes on the same id as the events
+ * of this module. When printing out the buffer, traced events left
+ * over from this module may be passed to the new module events and
+ * unexpected results may occur.
*/
if (clear_trace)
- tracing_reset_current_online_cpus();
- up_write(&trace_event_mutex);
+ tracing_reset_all_online_cpus();
}
static int trace_module_notify(struct notifier_block *self,