[tip:tracing/core] tracing/events: fix memory leak when unloading module

tip-bot for Li Zefan
2009-05-06T12:20:55Z

Commit-ID: 2df75e415709ad12862028916c772c1f377f6a7c
Gitweb: http://git.kernel.org/tip/2df75e415709ad12862028916c772c1f377f6a7c
Author: Li Zefan <lizf@cn.fujitsu.com>
AuthorDate: Wed, 6 May 2009 10:33:04 +0800
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 6 May 2009 10:38:19 +0200

tracing/events: fix memory leak when unloading module

When unloading a module, memory allocated by init_preds() and
trace_define_field() is not freed.

[ Impact: fix memory leak ]

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4A00F6E0.3040503@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
include/linux/ftrace_event.h | 1 +
kernel/trace/trace_events.c | 18 ++++++++++++++++++
kernel/trace/trace_events_filter.c | 22 +++++++++++++++-------
3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 5fff40c..662c1be 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -116,6 +116,7 @@ struct ftrace_event_call {
#define MAX_FILTER_STR_VAL 128

extern int init_preds(struct ftrace_event_call *call);
+extern void destroy_preds(struct ftrace_event_call *call);
extern int filter_match_preds(struct ftrace_event_call *call, void *rec);
extern int filter_current_check_discard(struct ftrace_event_call *call,
void *rec,
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f789ca5..f251a15 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -60,6 +60,22 @@ err:
}
EXPORT_SYMBOL_GPL(trace_define_field);

+#ifdef CONFIG_MODULES
+
+static void trace_destroy_fields(struct ftrace_event_call *call)
+{
+ struct ftrace_event_field *field, *next;
+
+ list_for_each_entry_safe(field, next, &call->fields, link) {
+ list_del(&field->link);
+ kfree(field->type);
+ kfree(field->name);
+ kfree(field);
+ }
+}
+
+#endif /* CONFIG_MODULES */
+
static void ftrace_clear_events(void)
{
struct ftrace_event_call *call;
@@ -925,6 +941,8 @@ static void trace_module_remove_events(struct module *mod)
unregister_ftrace_event(call->event);
debugfs_remove_recursive(call->dir);
list_del(&call->list);
+ trace_destroy_fields(call);
+ destroy_preds(call);
}
}

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index f494866..ce07b81 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -346,6 +346,20 @@ static void filter_disable_preds(struct ftrace_event_call *call)
filter->preds[i]->fn = filter_pred_none;
}

+void destroy_preds(struct ftrace_event_call *call)
+{
+ struct event_filter *filter = call->filter;
+ int i;
+
+ for (i = 0; i < MAX_FILTER_PRED; i++) {
+ if (filter->preds[i])
+ filter_free_pred(filter->preds[i]);
+ }
+ kfree(filter->preds);
+ kfree(filter);
+ call->filter = NULL;
+}
+
int init_preds(struct ftrace_event_call *call)
{
struct event_filter *filter;
@@ -374,13 +388,7 @@ int init_preds(struct ftrace_event_call *call)
return 0;

oom:
- for (i = 0; i < MAX_FILTER_PRED; i++) {
- if (filter->preds[i])
- filter_free_pred(filter->preds[i]);
- }
- kfree(filter->preds);
- kfree(call->filter);
- call->filter = NULL;
+ destroy_preds(call);

return -ENOMEM;
}