rfnoc: Fix potential double-overrun handling in rx stream terminator

It's feasible that error messages are sent out during overrun handling,
which would cause a nested invocation of handle_overrun(). This adds a
lock to prevent that.

2 files changed, 9 insertions, 0 deletions

diff --git a/host/lib/rfnoc/rx_stream_terminator.cpp b/host/lib/rfnoc/rx_stream_terminator.cpp
index e05d9cd49..7d38e2101 100644
--- a/host/lib/rfnoc/rx_stream_terminator.cpp
+++ b/host/lib/rfnoc/rx_stream_terminator.cpp
@@ -63,6 +63,12 @@ void rx_stream_terminator::set_rx_streamer(bool active, const size_t)
 
 void rx_stream_terminator::handle_overrun(boost::weak_ptr<uhd::rx_streamer> streamer, const size_t)
 {
+    std::unique_lock<std::mutex> l(_overrun_handler_mutex, std::defer_lock);
+    if (!l.try_lock()) {
+        // We're already handling overruns, so just stop right there
+        return;
+    }
+
     std::vector<boost::shared_ptr<uhd::rfnoc::radio_ctrl_impl> > upstream_radio_nodes =
         find_upstream_node<uhd::rfnoc::radio_ctrl_impl>();
     const size_t n_radios = upstream_radio_nodes.size();
diff --git a/host/lib/rfnoc/rx_stream_terminator.hpp b/host/lib/rfnoc/rx_stream_terminator.hpp
index 5159cd34a..fb205d00c 100644
--- a/host/lib/rfnoc/rx_stream_terminator.hpp
+++ b/host/lib/rfnoc/rx_stream_terminator.hpp
@@ -24,6 +24,7 @@
 #include <uhd/rfnoc/scalar_node_ctrl.hpp>
 #include <uhd/rfnoc/terminator_node_ctrl.hpp>
 #include <uhd/rfnoc/block_ctrl_base.hpp> // For the block macros
+#include <mutex>
 
 namespace uhd {
     namespace rfnoc {
@@ -78,6 +79,8 @@ private:
     double _samp_rate;
     double _tick_rate;
 
+    std::mutex _overrun_handler_mutex;
+
 }; /* class rx_stream_terminator */
 
 }} /* namespace uhd::rfnoc */