tracing: Protect ftrace_trace_arrays list in trace_events.c
There are multiple places where the ftrace_trace_arrays list is accessed in
trace_events.c without the trace_types_lock held.
Link: http://lkml.kernel.org/r/1372732674-22726-1-git-send-email-azl@google.com
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 5892470..35c6f23 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1008,6 +1008,7 @@
int ret;
/* Make sure the system still exists */
+ mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
list_for_each_entry(dir, &tr->systems, list) {
@@ -1023,6 +1024,7 @@
}
exit_loop:
mutex_unlock(&event_mutex);
+ mutex_unlock(&trace_types_lock);
if (!system)
return -ENODEV;
@@ -1617,6 +1619,7 @@
int trace_add_event_call(struct ftrace_event_call *call)
{
int ret;
+ mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
ret = __register_event(call, NULL);
@@ -1624,11 +1627,13 @@
__add_event_to_tracers(call, NULL);
mutex_unlock(&event_mutex);
+ mutex_unlock(&trace_types_lock);
return ret;
}
/*
- * Must be called under locking both of event_mutex and trace_event_sem.
+ * Must be called under locking of trace_types_lock, event_mutex and
+ * trace_event_sem.
*/
static void __trace_remove_event_call(struct ftrace_event_call *call)
{
@@ -1640,11 +1645,13 @@
/* Remove an event_call */
void trace_remove_event_call(struct ftrace_event_call *call)
{
+ mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
down_write(&trace_event_sem);
__trace_remove_event_call(call);
up_write(&trace_event_sem);
mutex_unlock(&event_mutex);
+ mutex_unlock(&trace_types_lock);
}
#define for_each_event(event, start, end) \
@@ -1788,6 +1795,7 @@
{
struct module *mod = data;
+ mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
switch (val) {
case MODULE_STATE_COMING:
@@ -1798,6 +1806,7 @@
break;
}
mutex_unlock(&event_mutex);
+ mutex_unlock(&trace_types_lock);
return 0;
}