---

yaml
---
r: 234480
b: refs/heads/master
c: c9c53ca
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 58d9a597c4275d830a819625e7d437cd6fb23fa5
+refs/heads/master: c9c53ca03d6f97fdd9832d5ed3f15b30ee5cdb86

trunk/kernel/trace/trace.h

@@ -661,7 +661,8 @@ struct ftrace_event_field {
 };
 
 struct event_filter {
-	int			n_preds;
+	int			n_preds;	/* Number assigned */
+	int			a_preds;	/* allocated */
 	struct filter_pred	**preds;
 	char			*filter_string;
 };

trunk/kernel/trace/trace_events_filter.c

@@ -362,6 +362,7 @@ int filter_match_preds(struct event_filter *filter, void *rec)
 {
 	int match = -1, top = 0, val1 = 0, val2 = 0;
 	int stack[MAX_FILTER_PRED];
+	struct filter_pred **preds;
 	struct filter_pred *pred;
 	int n_preds = ACCESS_ONCE(filter->n_preds);
 	int i;
@@ -370,8 +371,13 @@ int filter_match_preds(struct event_filter *filter, void *rec)
 	if (!n_preds)
 		return 1;
 
+	/*
+	 * n_preds and filter->preds is protect with preemption disabled.
+	 */
+	preds = rcu_dereference_sched(filter->preds);
+
 	for (i = 0; i < n_preds; i++) {
-		pred = filter->preds[i];
+		pred = preds[i];
 		if (!pred->pop_n) {
 			match = pred->fn(pred, rec);
 			stack[top++] = match;
@@ -548,79 +554,119 @@ static int filter_set_pred(struct filter_pred *dest,
 	return 0;
 }
 
+static void __free_preds(struct event_filter *filter)
+{
+	int i;
+
+	if (filter->preds) {
+		for (i = 0; i < filter->a_preds; i++) {
+			if (filter->preds[i])
+				filter_free_pred(filter->preds[i]);
+		}
+		kfree(filter->preds);
+		filter->preds = NULL;
+	}
+	filter->a_preds = 0;
+	filter->n_preds = 0;
+}
+
 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;
-
-	for (i = 0; i < MAX_FILTER_PRED; i++)
-		filter->preds[i]->fn = filter_pred_none;
 }
 
-static void __free_preds(struct event_filter *filter)
+static void __free_filter(struct event_filter *filter)
 {
-	int i;
-
 	if (!filter)
 		return;
 
-	for (i = 0; i < MAX_FILTER_PRED; i++) {
-		if (filter->preds[i])
-			filter_free_pred(filter->preds[i]);
-	}
-	kfree(filter->preds);
+	__free_preds(filter);
 	kfree(filter->filter_string);
 	kfree(filter);
 }
 
 void destroy_preds(struct ftrace_event_call *call)
 {
-	__free_preds(call->filter);
+	__free_filter(call->filter);
 	call->filter = NULL;
 	call->flags &= ~TRACE_EVENT_FL_FILTERED;
 }
 
-static struct event_filter *__alloc_preds(void)
+static struct event_filter *__alloc_filter(void)
 {
 	struct event_filter *filter;
-	struct filter_pred *pred;
-	int i;
 
 	filter = kzalloc(sizeof(*filter), GFP_KERNEL);
 	if (!filter)
 		return ERR_PTR(-ENOMEM);
 
 	filter->n_preds = 0;
 
-	filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
+	return filter;
+}
+
+static int __alloc_preds(struct event_filter *filter, int n_preds)
+{
+	struct filter_pred *pred;
+	int i;
+
+	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.
+			 */
+			synchronize_sched();
+			__free_preds(filter);
+		}
+	}
+
+	if (!filter->preds) {
+		filter->preds =
+			kzalloc(sizeof(*filter->preds) * n_preds, GFP_KERNEL);
+		filter->a_preds = n_preds;
+	}
 	if (!filter->preds)
-		goto oom;
+		return -ENOMEM;
+
+	if (WARN_ON(filter->a_preds < n_preds))
+		return -EINVAL;
 
-	for (i = 0; i < MAX_FILTER_PRED; i++) {
-		pred = kzalloc(sizeof(*pred), GFP_KERNEL);
+	for (i = 0; i < n_preds; i++) {
+		pred = filter->preds[i];
+		if (!pred)
+			pred = kzalloc(sizeof(*pred), GFP_KERNEL);
 		if (!pred)
 			goto oom;
 		pred->fn = filter_pred_none;
 		filter->preds[i] = pred;
 	}
 
-	return filter;
-
-oom:
+	return 0;
+ oom:
 	__free_preds(filter);
-	return ERR_PTR(-ENOMEM);
+	return -ENOMEM;
 }
 
-static int init_preds(struct ftrace_event_call *call)
+static int init_filter(struct ftrace_event_call *call)
 {
 	if (call->filter)
 		return 0;
 
 	call->flags &= ~TRACE_EVENT_FL_FILTERED;
-	call->filter = __alloc_preds();
+	call->filter = __alloc_filter();
 	if (IS_ERR(call->filter))
 		return PTR_ERR(call->filter);
 
@@ -636,7 +682,7 @@ static int init_subsystem_preds(struct event_subsystem *system)
 		if (strcmp(call->class->system, system->name) != 0)
 			continue;
 
-		err = init_preds(call);
+		err = init_filter(call);
 		if (err)
 			return err;
 	}
@@ -665,7 +711,7 @@ static int filter_add_pred_fn(struct filter_parse_state *ps,
 {
 	int idx, err;
 
-	if (filter->n_preds == MAX_FILTER_PRED) {
+	if (WARN_ON(filter->n_preds == filter->a_preds)) {
 		parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
 		return -ENOSPC;
 	}
@@ -1179,6 +1225,20 @@ static int check_preds(struct filter_parse_state *ps)
 	return 0;
 }
 
+static int count_preds(struct filter_parse_state *ps)
+{
+	struct postfix_elt *elt;
+	int n_preds = 0;
+
+	list_for_each_entry(elt, &ps->postfix, list) {
+		if (elt->op == OP_NONE)
+			continue;
+		n_preds++;
+	}
+
+	return n_preds;
+}
+
 static int replace_preds(struct ftrace_event_call *call,
 			 struct event_filter *filter,
 			 struct filter_parse_state *ps,
@@ -1191,10 +1251,23 @@ static int replace_preds(struct ftrace_event_call *call,
 	int err;
 	int n_preds = 0;
 
+	n_preds = count_preds(ps);
+	if (n_preds >= MAX_FILTER_PRED) {
+		parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
+		return -ENOSPC;
+	}
+
 	err = check_preds(ps);
 	if (err)
 		return err;
 
+	if (!dry_run) {
+		err = __alloc_preds(filter, n_preds);
+		if (err)
+			return err;
+	}
+
+	n_preds = 0;
 	list_for_each_entry(elt, &ps->postfix, list) {
 		if (elt->op == OP_NONE) {
 			if (!operand1)
@@ -1208,7 +1281,7 @@ static int replace_preds(struct ftrace_event_call *call,
 			continue;
 		}
 
-		if (n_preds++ == MAX_FILTER_PRED) {
+		if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
 			parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
 			return -ENOSPC;
 		}
@@ -1283,7 +1356,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
 
 	mutex_lock(&event_mutex);
 
-	err = init_preds(call);
+	err = init_filter(call);
 	if (err)
 		goto out_unlock;
 
@@ -1376,7 +1449,7 @@ void ftrace_profile_free_filter(struct perf_event *event)
 	struct event_filter *filter = event->filter;
 
 	event->filter = NULL;
-	__free_preds(filter);
+	__free_filter(filter);
 }
 
 int ftrace_profile_set_filter(struct perf_event *event, int event_id,
@@ -1402,7 +1475,7 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
 	if (event->filter)
 		goto out_unlock;
 
-	filter = __alloc_preds();
+	filter = __alloc_filter();
 	if (IS_ERR(filter)) {
 		err = PTR_ERR(filter);
 		goto out_unlock;
@@ -1411,7 +1484,7 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
 	err = -ENOMEM;
 	ps = kzalloc(sizeof(*ps), GFP_KERNEL);
 	if (!ps)
-		goto free_preds;
+		goto free_filter;
 
 	parse_init(ps, filter_ops, filter_str);
 	err = filter_parse(ps);
@@ -1427,9 +1500,9 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
 	postfix_clear(ps);
 	kfree(ps);
 
-free_preds:
+free_filter:
 	if (err)
-		__free_preds(filter);
+		__free_filter(filter);
 
 out_unlock:
 	mutex_unlock(&event_mutex);