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-rw-r--r--kernel/trace/trace_events_filter.c137
1 files changed, 86 insertions, 51 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 0948905..5b889d4 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -381,6 +381,63 @@ get_pred_parent(struct filter_pred *pred, struct filter_pred *preds,
return pred;
}
+enum walk_return {
+ WALK_PRED_ABORT,
+ WALK_PRED_PARENT,
+ WALK_PRED_DEFAULT,
+};
+
+typedef int (*filter_pred_walkcb_t) (enum move_type move,
+ struct filter_pred *pred,
+ int *err, void *data);
+
+static int walk_pred_tree(struct filter_pred *preds,
+ struct filter_pred *root,
+ filter_pred_walkcb_t cb, void *data)
+{
+ struct filter_pred *pred = root;
+ enum move_type move = MOVE_DOWN;
+ int done = 0;
+
+ if (!preds)
+ return -EINVAL;
+
+ do {
+ int err = 0, ret;
+
+ ret = cb(move, pred, &err, data);
+ if (ret == WALK_PRED_ABORT)
+ return err;
+ if (ret == WALK_PRED_PARENT)
+ goto get_parent;
+
+ switch (move) {
+ case MOVE_DOWN:
+ if (pred->left != FILTER_PRED_INVALID) {
+ pred = &preds[pred->left];
+ continue;
+ }
+ goto get_parent;
+ case MOVE_UP_FROM_LEFT:
+ pred = &preds[pred->right];
+ move = MOVE_DOWN;
+ continue;
+ case MOVE_UP_FROM_RIGHT:
+ get_parent:
+ if (pred == root)
+ break;
+ pred = get_pred_parent(pred, preds,
+ pred->parent,
+ &move);
+ continue;
+ }
+ done = 1;
+ } while (!done);
+
+ /* We are fine. */
+ return 0;
+}
+
/*
* A series of AND or ORs where found together. Instead of
* climbing up and down the tree branches, an array of the
@@ -1321,6 +1378,23 @@ static int count_preds(struct filter_parse_state *ps)
return n_preds;
}
+struct check_pred_data {
+ int count;
+ int max;
+};
+
+static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ struct check_pred_data *d = data;
+
+ if (WARN_ON(d->count++ > d->max)) {
+ *err = -EINVAL;
+ return WALK_PRED_ABORT;
+ }
+ return WALK_PRED_DEFAULT;
+}
+
/*
* The tree is walked at filtering of an event. If the tree is not correctly
* built, it may cause an infinite loop. Check here that the tree does
@@ -1329,58 +1403,19 @@ static int count_preds(struct filter_parse_state *ps)
static int check_pred_tree(struct event_filter *filter,
struct filter_pred *root)
{
- struct filter_pred *preds;
- struct filter_pred *pred;
- enum move_type move = MOVE_DOWN;
- int count = 0;
- int done = 0;
- int max;
-
- /*
- * The max that we can hit a node is three times.
- * Once going down, once coming up from left, and
- * once coming up from right. This is more than enough
- * since leafs are only hit a single time.
- */
- max = 3 * filter->n_preds;
-
- preds = filter->preds;
- if (!preds)
- return -EINVAL;
- pred = root;
-
- do {
- if (WARN_ON(count++ > max))
- return -EINVAL;
-
- switch (move) {
- case MOVE_DOWN:
- if (pred->left != FILTER_PRED_INVALID) {
- pred = &preds[pred->left];
- continue;
- }
- /* A leaf at the root is just a leaf in the tree */
- if (pred == root)
- break;
- pred = get_pred_parent(pred, preds,
- pred->parent, &move);
- continue;
- case MOVE_UP_FROM_LEFT:
- pred = &preds[pred->right];
- move = MOVE_DOWN;
- continue;
- case MOVE_UP_FROM_RIGHT:
- if (pred == root)
- break;
- pred = get_pred_parent(pred, preds,
- pred->parent, &move);
- continue;
- }
- done = 1;
- } while (!done);
+ struct check_pred_data data = {
+ /*
+ * The max that we can hit a node is three times.
+ * Once going down, once coming up from left, and
+ * once coming up from right. This is more than enough
+ * since leafs are only hit a single time.
+ */
+ .max = 3 * filter->n_preds,
+ .count = 0,
+ };
- /* We are fine. */
- return 0;
+ return walk_pred_tree(filter->preds, root,
+ check_pred_tree_cb, &data);
}
static int count_leafs(struct filter_pred *preds, struct filter_pred *root)
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