src/looper.c

@@ -30,6 +30,10 @@ spsc_queue_t cmd_queue;
 static int pending_unregister_idx = -1;
 static int pending_unregister_cycle = 0;
 
+/* Deferred free of old channel array (must not free while RT thread may hold pointer) */
+static struct channel_t *pending_old = NULL;
+static int pending_old_cycle = 0;
+
 /* Helper: grow the channel array so that index idx is valid */
 static int ensure_capacity(jack_client_t *client, int idx) {
     (void)client;
@@ -45,10 +49,12 @@ static int ensure_capacity(jack_client_t *client, int idx) {
     /* copy existing channels */
     if (cur_cap > 0)
         memcpy(new_arr, atomic_load(&channels), cur_cap * sizeof(struct channel_t));
-    /* atomically publish new array */
+    /* atomically publish new array, defer free of old */
     struct channel_t *old = atomic_exchange(&channels, new_arr);
     atomic_store(&channel_capacity, new_cap);
-    free(old);
+    /* schedule old pointer for later deallocation (after RT cycle) */
+    pending_old = old;
+    pending_old_cycle = atomic_load(&global_rt_cycles);
     return 0;
 }
 
@@ -397,4 +403,13 @@ void looper_process_commands(jack_client_t *client) {
       pending_unregister_idx = -1;
     }
   }
+
+  /* Deferred free of old channel array – wait until RT thread has seen new pointer */
+  if (pending_old != NULL) {
+    int current_cycle = atomic_load(&global_rt_cycles);
+    if (current_cycle - pending_old_cycle >= 1) {
+      free(pending_old);
+      pending_old = NULL;
+    }
+  }
 }