+ if (attr->attr.subbuf_size < DEFAULT_UST_CHANNEL_SUBBUF_SIZE) {
+ ret = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ /*
+ * Validate UST buffer size and number of buffers: must both be power of 2
+ * and nonzero. We validate right here for UST, because applications will
+ * not report the error to the user (unlike kernel tracing).
+ */
+ if (!attr->attr.subbuf_size ||
+ (attr->attr.subbuf_size & (attr->attr.subbuf_size - 1))) {
+ ret = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ if (!attr->attr.num_subbuf ||
+ (attr->attr.num_subbuf & (attr->attr.num_subbuf - 1))) {
+ ret = LTTNG_ERR_INVALID;
+ goto error;
+ }
+
+ if (attr->attr.output != LTTNG_EVENT_MMAP) {
+ ret = LTTNG_ERR_NOT_SUPPORTED;
+ goto error;
+ }
+