Fix: consumerd: unbalanced subbuffer 'get' when checking operation availability

[lttng-tools.git] / src / common / kernel-consumer / kernel-consumer.c

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 083c8c0c7143b5c1048221f3868916885e3d90bf..4f734294caa553477f46eb0858edc45b3476b1e9 100644 (file)
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -1699,8 +1699,15 @@ int put_next_subbuffer(struct lttng_consumer_stream *stream,
 static
 bool is_get_next_check_metadata_available(int tracer_fd)
 {
-       return kernctl_get_next_subbuf_metadata_check(tracer_fd, NULL) !=
-                       -ENOTTY;
+       const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, NULL);
+       const bool available = ret != -ENOTTY;
+
+       if (ret == 0) {
+               /* get succeeded, make sure to put the subbuffer. */
+               kernctl_put_subbuf(tracer_fd);
+       }
+
+       return available;
 }
 
 static