tracing/filters: add filter_mutex to protect filter predicates
This patch adds a filter_mutex to prevent the filter predicates from
being accessed concurrently by various external functions.
It's based on a previous patch by Li Zefan:
"[PATCH 7/7] tracing/filters: make filter preds RCU safe"
v2 changes:
- fixed wrong value returned in a add_subsystem_pred() failure case
noticed by Li Zefan.
[ Impact: fix trace filter corruption/crashes on parallel access ]
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: paulmck@linux.vnet.ibm.com
LKML-Reference: <1239946028.6639.13.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8817c18..247948e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -757,13 +757,15 @@
};
extern void filter_free_pred(struct filter_pred *pred);
-extern void filter_print_preds(struct filter_pred **preds, int n_preds,
+extern void filter_print_preds(struct ftrace_event_call *call,
struct trace_seq *s);
extern int filter_parse(char **pbuf, struct filter_pred *pred);
extern int filter_add_pred(struct ftrace_event_call *call,
struct filter_pred *pred);
extern void filter_disable_preds(struct ftrace_event_call *call);
extern void filter_free_subsystem_preds(struct event_subsystem *system);
+extern void filter_print_subsystem_preds(struct event_subsystem *system,
+ struct trace_seq *s);
extern int filter_add_subsystem_pred(struct event_subsystem *system,
struct filter_pred *pred);