1 files changed, 35 insertions, 10 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 1880a6438097..769dfd00fc85 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -102,7 +102,7 @@ static int ftrace_set_clr_event(char *buf, int set)
         mutex_lock(&event_mutex);
         events_for_each(call) {
 
-                if (!call->name)
+                if (!call->name || !call->regfunc)
                         continue;
 
                 if (match &&
@@ -207,8 +207,20 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
         (*pos)++;
 
-        if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
-                return NULL;
+        for (;;) {
+                if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
+                        return NULL;
+
+                /*
+                 * The ftrace subsystem is for showing formats only.
+                 * They can not be enabled or disabled via the event files.
+                 */
+                if (call->regfunc)
+                        break;
+
+                call++;
+                next = call;
+        }
 
         m->private = ++next;
 
@@ -338,8 +350,7 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 
 #undef FIELD
 #define FIELD(type, name)                                               \
-        #type, #name, (unsigned int)offsetof(typeof(field), name),      \
-                (unsigned int)sizeof(field.name)
+        #type, #name, offsetof(typeof(field), name), sizeof(field.name)
 
 static int trace_write_header(struct trace_seq *s)
 {
@@ -347,11 +358,11 @@ static int trace_write_header(struct trace_seq *s)
 
         /* struct trace_entry */
         return trace_seq_printf(s,
-                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
-                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
-                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
-                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
-                                "\tfield:%s %s;\toffset:%u;\tsize:%u;\n"
+                                "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
+                                "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
+                                "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
+                                "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
+                                "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n"
                                 "\n",
                                 FIELD(unsigned char, type),
                                 FIELD(unsigned char, flags),
@@ -417,6 +428,13 @@ static const struct seq_operations show_set_event_seq_ops = {
         .stop = t_stop,
 };
 
+static const struct file_operations ftrace_avail_fops = {
+        .open = ftrace_event_seq_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = seq_release,
+};
+
 static const struct file_operations ftrace_set_event_fops = {
         .open = ftrace_event_seq_open,
         .read = seq_read,
@@ -558,6 +576,13 @@ static __init int event_trace_init(void)
         if (!d_tracer)
                 return 0;
 
+        entry = debugfs_create_file("available_events", 0444, d_tracer,
+                                    (void *)&show_event_seq_ops,
+                                    &ftrace_avail_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'available_events' entry\n");
+
         entry = debugfs_create_file("set_event", 0644, d_tracer,
                                     (void *)&show_set_event_seq_ops,
                                     &ftrace_set_event_fops);