From d8a30f20347a60a796a5221e07711c0d30d42dc3 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Sat, 21 Dec 2013 21:55:17 -0500 Subject: [PATCH] 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 Tested-by: Tom Zanussi Acked-by: Tom Zanussi Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 2 +- kernel/trace/trace_events_trigger.c | 8 +++++--- 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; } -- GitLab