tracing: Fix bug when reading system filters on module removal

[linux-imx.git] / kernel / trace / trace_events_filter.c

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 8008ddcfbf20add080624f6714a5b38424b3789e..256764ecccd66fca5045cf0a53bb9d04d8e7f106 100644 (file)
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -1886,6 +1886,12 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
 
        mutex_lock(&event_mutex);
 
+       /* Make sure the system still has events */
+       if (!system->nr_events) {
+               err = -ENODEV;
+               goto out_unlock;
+       }
+
        if (!strcmp(strstrip(filter_string), "0")) {
                filter_free_subsystem_preds(system);
                remove_filter_string(system->filter);