tracing: add protection around modify trace event fields
The trace event objects are currently not proctected against
reentrancy. This patch adds a mutex around the modifications of
the trace event fields.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1d07f80..26069fa 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -14,6 +14,8 @@
#define TRACE_SYSTEM "TRACE_SYSTEM"
+static DEFINE_MUTEX(event_mutex);
+
#define events_for_each(event) \
for (event = __start_ftrace_events; \
(unsigned long)event < (unsigned long)__stop_ftrace_events; \
@@ -104,6 +106,7 @@
event = NULL;
}
+ mutex_lock(&event_mutex);
events_for_each(call) {
if (!call->name)
@@ -124,6 +127,8 @@
ret = 0;
}
+ mutex_unlock(&event_mutex);
+
return ret;
}
@@ -324,7 +329,9 @@
switch (val) {
case 0:
case 1:
+ mutex_lock(&event_mutex);
ftrace_event_enable_disable(call, val);
+ mutex_unlock(&event_mutex);
break;
default: