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-rw-r--r--kernel/trace/trace_events.c4
-rw-r--r--kernel/trace/trace_output.c15
-rw-r--r--kernel/trace/trace_output.h4
3 files changed, 19 insertions, 4 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6c81f9c2142..aa08be69a1b 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1050,12 +1050,13 @@ static void trace_module_remove_events(struct module *mod)
struct ftrace_event_call *call, *p;
bool found = false;
+ down_write(&trace_event_mutex);
list_for_each_entry_safe(call, p, &ftrace_events, list) {
if (call->mod == mod) {
found = true;
ftrace_event_enable_disable(call, 0);
if (call->event)
- unregister_ftrace_event(call->event);
+ __unregister_ftrace_event(call->event);
debugfs_remove_recursive(call->dir);
list_del(&call->list);
trace_destroy_fields(call);
@@ -1079,6 +1080,7 @@ static void trace_module_remove_events(struct module *mod)
*/
if (found)
tracing_reset_current_online_cpus();
+ up_write(&trace_event_mutex);
}
static int trace_module_notify(struct notifier_block *self,
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index c05aff465dc..7938f3ae93e 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -14,7 +14,7 @@
/* must be a power of 2 */
#define EVENT_HASHSIZE 128
-static DECLARE_RWSEM(trace_event_mutex);
+DECLARE_RWSEM(trace_event_mutex);
DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);
EXPORT_PER_CPU_SYMBOL(ftrace_event_seq);
@@ -702,6 +702,16 @@ int register_ftrace_event(struct trace_event *event)
}
EXPORT_SYMBOL_GPL(register_ftrace_event);
+/*
+ * Used by module code with the trace_event_mutex held for write.
+ */
+int __unregister_ftrace_event(struct trace_event *event)
+{
+ hlist_del(&event->node);
+ list_del(&event->list);
+ return 0;
+}
+
/**
* unregister_ftrace_event - remove a no longer used event
* @event: the event to remove
@@ -709,8 +719,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_event);
int unregister_ftrace_event(struct trace_event *event)
{
down_write(&trace_event_mutex);
- hlist_del(&event->node);
- list_del(&event->list);
+ __unregister_ftrace_event(event);
up_write(&trace_event_mutex);
return 0;
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index ac240e76eb0..d38bec4a9c3 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -27,6 +27,10 @@ extern struct trace_event *ftrace_find_event(int type);
extern enum print_line_t trace_nop_print(struct trace_iterator *iter,
int flags);
+/* used by module unregistering */
+extern int __unregister_ftrace_event(struct trace_event *event);
+extern struct rw_semaphore trace_event_mutex;
+
#define MAX_MEMHEX_BYTES 8
#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)