diff options
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 80 |
1 files changed, 63 insertions, 17 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index aac6a6183e6a..8f00a11ce778 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -570,17 +570,28 @@ static void __free_preds(struct event_filter *filter) filter->n_preds = 0; } +static void reset_preds(struct event_filter *filter) +{ + struct filter_pred *pred; + int n_preds = filter->n_preds; + int i; + + filter->n_preds = 0; + if (!filter->preds) + return; + + for (i = 0; i < n_preds; i++) { + pred = filter->preds[i]; + pred->fn = filter_pred_none; + } +} + static void filter_disable_preds(struct ftrace_event_call *call) { struct event_filter *filter = call->filter; - int i; call->flags &= ~TRACE_EVENT_FL_FILTERED; - if (filter->preds) { - for (i = 0; i < filter->n_preds; i++) - filter->preds[i]->fn = filter_pred_none; - } - filter->n_preds = 0; + reset_preds(filter); } static void __free_filter(struct event_filter *filter) @@ -620,15 +631,17 @@ static int __alloc_preds(struct event_filter *filter, int n_preds) if (filter->preds) { if (filter->a_preds < n_preds) { - /* We need to reallocate */ - filter->n_preds = 0; /* - * It is possible that the filter is currently - * being used. We need to zero out the number - * of preds, wait on preemption and then free - * the preds. + * We need to reallocate. + * We should have already have zeroed out + * the pred count and called synchronized_sched() + * to make sure no one is using the preds. */ - synchronize_sched(); + if (WARN_ON_ONCE(filter->n_preds)) { + /* We need to reset it now */ + filter->n_preds = 0; + synchronize_sched(); + } __free_preds(filter); } } @@ -1328,6 +1341,30 @@ static int replace_system_preds(struct event_subsystem *system, /* try to see if the filter can be applied */ err = replace_preds(call, filter, ps, filter_string, true); if (err) + goto fail; + } + + /* set all filter pred counts to zero */ + list_for_each_entry(call, &ftrace_events, list) { + struct event_filter *filter = call->filter; + + if (strcmp(call->class->system, system->name) != 0) + continue; + + reset_preds(filter); + } + + /* + * Since some of the preds may be used under preemption + * we need to wait for them to finish before we may + * reallocate them. + */ + synchronize_sched(); + + list_for_each_entry(call, &ftrace_events, list) { + struct event_filter *filter = call->filter; + + if (strcmp(call->class->system, system->name) != 0) continue; /* really apply the filter */ @@ -1342,11 +1379,13 @@ static int replace_system_preds(struct event_subsystem *system, fail = false; } - if (fail) { - parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0); - return -EINVAL; - } + if (fail) + goto fail; + return 0; + fail: + parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0); + return -EINVAL; } int apply_event_filter(struct ftrace_event_call *call, char *filter_string) @@ -1381,6 +1420,13 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) goto out; } + /* + * Make sure all the pred counts are zero so that + * no task is using it when we reallocate the preds array. + */ + reset_preds(call->filter); + synchronize_sched(); + err = replace_preds(call, call->filter, ps, filter_string, false); if (err) append_filter_err(ps, call->filter); |