tracing: Fix race between deleting buffer and setting events

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / trace / trace_events.c

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 920e08f..7d85429 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -441,14 +441,14 @@ static int tracing_release_generic_file(struct inode *inode, struct file *filp)
 /*
  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
  */
-static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
-                                 const char *sub, const char *event, int set)
+static int
+__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
+                             const char *sub, const char *event, int set)
 {
        struct ftrace_event_file *file;
        struct ftrace_event_call *call;
        int ret = -EINVAL;
 
-       mutex_lock(&event_mutex);
        list_for_each_entry(file, &tr->events, list) {
 
                call = file->event_call;
@@ -474,6 +474,17 @@ static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
 
                ret = 0;
        }
+
+       return ret;
+}
+
+static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
+                                 const char *sub, const char *event, int set)
+{
+       int ret;
+
+       mutex_lock(&event_mutex);
+       ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
        mutex_unlock(&event_mutex);
 
        return ret;
@@ -2408,11 +2419,11 @@ early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
 
 int event_trace_del_tracer(struct trace_array *tr)
 {
-       /* Disable any running events */
-       __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
-
        mutex_lock(&event_mutex);
 
+       /* Disable any running events */
+       __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
+
        down_write(&trace_event_sem);
        __trace_remove_event_dirs(tr);
        debugfs_remove_recursive(tr->event_dir);