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authorSteven Rostedt <srostedt@redhat.com>2011-01-27 22:33:26 -0500
committerSteven Rostedt <rostedt@goodmis.org>2011-02-07 20:56:17 -0500
commit6d54057d76e25c91165cda0e6e007f1811faa2be (patch)
tree5f797433b9604e645e068a85c6f708db8b9dfbcd /kernel/trace
parent075de90c46562de1435db16c2129ec4ff92e5bd2 (diff)
tracing/filter: Have no filter return a match
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 <tzanussi@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_events_filter.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 36d40104b17f..7275f0310ed8 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);