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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-12-21 21:55:17 -0500
committerSteven Rostedt <rostedt@goodmis.org>2014-01-02 16:17:22 -0500
commitd8a30f20347a60a796a5221e07711c0d30d42dc3 (patch)
treeeed4dc37ddf15b981194a573701522605b58e69f /kernel/trace
parent098c879e1f2d6ee7afbfe959f6b04070065cec90 (diff)
tracing: Fix rcu handling of event_trigger_data filter field
The filter field of the event_trigger_data structure is protected under RCU sched locks. It was not annotated as such, and after doing so, sparse pointed out several locations that required fix ups. Reported-by: kbuild test robot <fengguang.wu@intel.com> Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com> Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.h2
-rw-r--r--kernel/trace/trace_events_trigger.c8
2 files changed, 6 insertions, 4 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 0380cab0af9b..02b592f2d4b7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1057,7 +1057,7 @@ struct event_trigger_data {
int ref;
struct event_trigger_ops *ops;
struct event_command *cmd_ops;
- struct event_filter *filter;
+ struct event_filter __rcu *filter;
char *filter_str;
void *private_data;
struct list_head list;
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 12ac8a5d4d95..f6dd115b958d 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -67,6 +67,7 @@ event_triggers_call(struct ftrace_event_file *file, void *rec)
{
struct event_trigger_data *data;
enum event_trigger_type tt = ETT_NONE;
+ struct event_filter *filter;
if (list_empty(&file->triggers))
return tt;
@@ -76,7 +77,8 @@ event_triggers_call(struct ftrace_event_file *file, void *rec)
data->ops->func(data);
continue;
}
- if (data->filter && !filter_match_preds(data->filter, rec))
+ filter = rcu_dereference(data->filter);
+ if (filter && !filter_match_preds(filter, rec))
continue;
if (data->cmd_ops->post_trigger) {
tt |= data->cmd_ops->trigger_type;
@@ -703,7 +705,7 @@ static int set_trigger_filter(char *filter_str,
if (ret)
goto out;
assign:
- tmp = data->filter;
+ tmp = rcu_access_pointer(data->filter);
rcu_assign_pointer(data->filter, filter);
@@ -719,7 +721,7 @@ static int set_trigger_filter(char *filter_str,
if (filter_str) {
data->filter_str = kstrdup(filter_str, GFP_KERNEL);
if (!data->filter_str) {
- free_event_filter(data->filter);
+ free_event_filter(rcu_access_pointer(data->filter));
data->filter = NULL;
ret = -ENOMEM;
}