1 files changed, 2 insertions, 0 deletions
diff --git a/Alc/backends/null.c b/Alc/backends/null.c
index 5b153cd9..41636538 100644
--- a/Alc/backends/null.c
+++ b/Alc/backends/null.c
@@ -109,7 +109,9 @@ static int ALCnullBackend_mixerProc(void *ptr)
             al_nssleep(restTime);
         else while(avail-done >= device->UpdateSize)
         {
+            ALCnullBackend_lock(self);
             aluMixData(device, NULL, device->UpdateSize);
+            ALCnullBackend_unlock(self);
             done += device->UpdateSize;
         }
     }