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Diffstat (limited to 'kernel/trace/trace_events.c')
-rw-r--r--kernel/trace/trace_events.c54
1 files changed, 41 insertions, 13 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53582e982e51..7a0cf68027cc 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -251,7 +251,8 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
switch (enable) {
case 0:
/*
- * When soft_disable is set and enable is cleared, we want
+ * When soft_disable is set and enable is cleared, the sm_ref
+ * reference counter is decremented. If it reaches 0, we want
* to clear the SOFT_DISABLED flag but leave the event in the
* state that it was. That is, if the event was enabled and
* SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
@@ -263,6 +264,8 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
* "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
*/
if (soft_disable) {
+ if (atomic_dec_return(&file->sm_ref) > 0)
+ break;
disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
} else
@@ -291,8 +294,11 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
*/
if (!soft_disable)
clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
- else
+ else {
+ if (atomic_inc_return(&file->sm_ref) > 1)
+ break;
set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
+ }
if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
@@ -623,6 +629,8 @@ event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
if (file->flags & FTRACE_EVENT_FL_ENABLED) {
if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED)
buf = "0*\n";
+ else if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
+ buf = "1*\n";
else
buf = "1\n";
} else
@@ -1521,6 +1529,24 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
return 0;
}
+static struct ftrace_event_file *
+trace_create_new_event(struct ftrace_event_call *call,
+ struct trace_array *tr)
+{
+ struct ftrace_event_file *file;
+
+ file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ if (!file)
+ return NULL;
+
+ file->event_call = call;
+ file->tr = tr;
+ atomic_set(&file->sm_ref, 0);
+ list_add(&file->list, &tr->events);
+
+ return file;
+}
+
/* Add an event to a trace directory */
static int
__trace_add_new_event(struct ftrace_event_call *call,
@@ -1532,14 +1558,10 @@ __trace_add_new_event(struct ftrace_event_call *call,
{
struct ftrace_event_file *file;
- file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ file = trace_create_new_event(call, tr);
if (!file)
return -ENOMEM;
- file->event_call = call;
- file->tr = tr;
- list_add(&file->list, &tr->events);
-
return event_create_dir(tr->event_dir, file, id, enable, filter, format);
}
@@ -1554,14 +1576,10 @@ __trace_early_add_new_event(struct ftrace_event_call *call,
{
struct ftrace_event_file *file;
- file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+ file = trace_create_new_event(call, tr);
if (!file)
return -ENOMEM;
- file->event_call = call;
- file->tr = tr;
- list_add(&file->list, &tr->events);
-
return 0;
}
@@ -2061,8 +2079,18 @@ event_enable_func(struct ftrace_hash *hash,
if (ret < 0)
goto out_put;
ret = register_ftrace_function_probe(glob, ops, data);
- if (!ret)
+ /*
+ * The above returns on success the # of functions enabled,
+ * but if it didn't find any functions it returns zero.
+ * Consider no functions a failure too.
+ */
+ if (!ret) {
+ ret = -ENOENT;
+ goto out_disable;
+ } else if (ret < 0)
goto out_disable;
+ /* Just return zero, not the number of enabled functions */
+ ret = 0;
out:
mutex_unlock(&event_mutex);
return ret;