diff options
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 86040d9c1acc..fdc6d22d406b 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -27,6 +27,12 @@ #include "trace.h" #include "trace_output.h" +#define DEFAULT_SYS_FILTER_MESSAGE \ + "### global filter ###\n" \ + "# Use this to set filters for multiple events.\n" \ + "# Only events with the given fields will be affected.\n" \ + "# If no events are modified, an error message will be displayed here" + enum filter_op_ids { OP_OR, @@ -646,7 +652,7 @@ void print_subsystem_event_filter(struct event_subsystem *system, if (filter && filter->filter_string) trace_seq_printf(s, "%s\n", filter->filter_string); else - trace_seq_printf(s, "none\n"); + trace_seq_printf(s, DEFAULT_SYS_FILTER_MESSAGE "\n"); mutex_unlock(&event_mutex); } @@ -1838,7 +1844,10 @@ int apply_subsystem_event_filter(struct event_subsystem *system, if (!filter) goto out; - replace_filter_string(filter, filter_string); + /* System filters just show a default message */ + kfree(filter->filter_string); + filter->filter_string = NULL; + /* * No event actually uses the system filter * we can free it without synchronize_sched(). @@ -1848,14 +1857,12 @@ int apply_subsystem_event_filter(struct event_subsystem *system, parse_init(ps, filter_ops, filter_string); err = filter_parse(ps); - if (err) { - append_filter_err(ps, system->filter); - goto out; - } + if (err) + goto err_filter; err = replace_system_preds(system, ps, filter_string); if (err) - append_filter_err(ps, system->filter); + goto err_filter; out: filter_opstack_clear(ps); @@ -1865,6 +1872,11 @@ out_unlock: mutex_unlock(&event_mutex); return err; + +err_filter: + replace_filter_string(filter, filter_string); + append_filter_err(ps, system->filter); + goto out; } #ifdef CONFIG_PERF_EVENTS |