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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>
hifive-unleashed-5.1
Steven Rostedt (Red Hat) 2013-12-21 21:55:17 -05:00 committed by Steven Rostedt
parent 098c879e1f
commit d8a30f2034
2 changed files with 6 additions and 4 deletions
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2
kernel/trace/trace.h
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@ -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;

8
kernel/trace/trace_events_trigger.c
View File

@ -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;
}