From: Steven Rostedt The n_preds field of a file can change at anytime, and even can become zero, just as the filter is about to be processed by an event. In the case that is zero on entering the filter, return 1, telling the caller the event matchs and should be trace. Also use a variable and assign it with ACCESS_ONCE() such that the count stays consistent within the function. Cc: Tom Zanussi Signed-off-by: Steven Rostedt --- kernel/trace/trace_events_filter.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 36d4010..7275f03 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -383,9 +383,14 @@ int filter_match_preds(struct event_filter *filter, void *rec) int match, top = 0, val1 = 0, val2 = 0; int stack[MAX_FILTER_PRED]; struct filter_pred *pred; + int n_preds = ACCESS_ONCE(filter->n_preds); int i; - for (i = 0; i < filter->n_preds; i++) { + /* no filter is considered a match */ + if (!n_preds) + return 1; + + for (i = 0; i < n_preds; i++) { pred = filter->preds[i]; if (!pred->pop_n) { match = pred->fn(pred, rec, val1, val2); -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/