From: "Steven Rostedt (Red Hat)" <srost...@redhat.com>
The new multi-buffers added a descriptor that kept track of module
events, and the directories they use, with struct ftace_module_file_ops.
This is used to add a ref count to keep modules from unloading while
their files are being accessed.
As the descriptor is only needed when CONFIG_MODULES is enabled, it
is only declared when the config is enabled. But that struct is
dereferenced in a few areas outside the #ifdef CONFIG_MODULES.
By adding some helper routines and moving code around a little,
events can be compiled again without modules.
Reported-by: Fengguang Wu <fengguang...@intel.com>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
kernel/trace/trace_events.c | 55 ++++++++++++++++++++++++++++---------------
1 file changed, 36 insertions(+), 19 deletions(-)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 63b4bdf..0f1307a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1546,9 +1546,18 @@ struct ftrace_module_file_ops {
struct file_operations filter;
};
-static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod)
+static struct ftrace_module_file_ops *
+find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module
*mod)
{
- struct ftrace_module_file_ops *file_ops;
+ /*
+ * As event_calls are added in groups by module,
+ * when we find one file_ops, we don't need to search for
+ * each call in that module, as the rest should be the
+ * same. Only search for a new one if the last one did
+ * not match.
+ */
+ if (file_ops && mod == file_ops->mod)
+ return file_ops;
list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
if (file_ops->mod == mod)
@@ -1664,16 +1673,35 @@ static int trace_module_notify(struct notifier_block
*self,
return 0;
}
+
+static int
+__trace_add_new_mod_event(struct ftrace_event_call *call,
+ struct trace_array *tr,
+ struct ftrace_module_file_ops *file_ops)
+{
+ return __trace_add_new_event(call, tr,
+ &file_ops->id, &file_ops->enable,
+ &file_ops->filter, &file_ops->format);
+}
+
#else
-static struct ftrace_module_file_ops *find_ftrace_file_ops(struct module *mod)
+static inline struct ftrace_module_file_ops *
+find_ftrace_file_ops(struct ftrace_module_file_ops *file_ops, struct module
*mod)
{
return NULL;
}
-static int trace_module_notify(struct notifier_block *self,
- unsigned long val, void *data)
+static inline int trace_module_notify(struct notifier_block *self,
+ unsigned long val, void *data)
{
return 0;
}
+static inline int
+__trace_add_new_mod_event(struct ftrace_event_call *call,
+ struct trace_array *tr,
+ struct ftrace_module_file_ops *file_ops)
+{
+ return -ENODEV;
+}
#endif /* CONFIG_MODULES */
/* Create a new event directory structure for a trace directory. */
@@ -1692,20 +1720,11 @@ __trace_add_event_dirs(struct trace_array *tr)
* want the module to disappear when reading one
* of these files). The file_ops keep account of
* the module ref count.
- *
- * As event_calls are added in groups by module,
- * when we find one file_ops, we don't need to search
for
- * each call in that module, as the rest should be the
- * same. Only search for a new one if the last one did
- * not match.
*/
- if (!file_ops || call->mod != file_ops->mod)
- file_ops = find_ftrace_file_ops(call->mod);
+ file_ops = find_ftrace_file_ops(file_ops, call->mod);
if (!file_ops)
continue; /* Warn? */
- ret = __trace_add_new_event(call, tr,
- &file_ops->id, &file_ops->enable,
- &file_ops->filter, &file_ops->format);
+ ret = __trace_add_new_mod_event(call, tr, file_ops);
if (ret < 0)
pr_warning("Could not create directory for
event %s\n",
call->name);
@@ -1794,9 +1813,7 @@ __add_event_to_tracers(struct ftrace_event_call *call,
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (file_ops)
- __trace_add_new_event(call, tr,
- &file_ops->id, &file_ops->enable,
- &file_ops->filter,
&file_ops->format);
+ __trace_add_new_mod_event(call, tr, file_ops);
else
__trace_add_new_event(call, tr,
&ftrace_event_id_fops,
--
1.7.10.4
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