diff --git a/src/cubeb_audiounit.cpp b/src/cubeb_audiounit.cpp
index e5e1529..0133ce7 100644
--- a/src/cubeb_audiounit.cpp
+++ b/src/cubeb_audiounit.cpp
@@ -79,7 +79,7 @@ struct cubeb {
   // The queue is asynchronously deallocated once all references to it are released
   dispatch_queue_t serial_queue = dispatch_queue_create(DISPATCH_QUEUE_LABEL, DISPATCH_QUEUE_SERIAL);
   // Current used channel layout
-  cubeb_channel_layout layout;
+  std::atomic<cubeb_channel_layout> layout{ CUBEB_LAYOUT_UNDEFINED };
 };
 
 static std::unique_ptr<AudioChannelLayout, decltype(&free)>
diff --git a/test/test_deadlock.cpp b/test/test_deadlock.cpp
index 64ca6e7..42301ac 100644
--- a/test/test_deadlock.cpp
+++ b/test/test_deadlock.cpp
@@ -52,6 +52,7 @@
 #include <stdexcept>      // for std::logic_error
 #include <string>         // for std::string
 #include <unistd.h>       // for sleep, usleep
+#include <atomic>         // for std::atomic
 
 // The signal alias for calling our thread killer.
 #define CALL_THREAD_KILLER SIGUSR1
@@ -61,7 +62,7 @@
 bool killed = false;
 
 // This indicator will become true when the assigned task is done.
-bool task_done = false;
+std::atomic<bool> task_done{ false };
 
 // Indicating the data callback is fired or not.
 bool called = false;
@@ -69,7 +70,7 @@ bool called = false;
 // Toggle to true when running data callback. Before data callback gets
 // the mutex for cubeb context, it toggles back to false.
 // The task to get channel layout should be executed when this is true.
-bool callbacking_before_getting_context = false;
+std::atomic<bool> callbacking_before_getting_context{ false };
 
 owned_critical_section context_mutex;
 cubeb * context = nullptr;
@@ -242,11 +243,11 @@ TEST(cubeb, run_deadlock_test)
 
   ASSERT_TRUE(called);
 
-  fprintf(stderr, "\n%sDeadlock detected!\n", (called && !task_done) ? "" : "No ");
+  fprintf(stderr, "\n%sDeadlock detected!\n", (called && !task_done.load()) ? "" : "No ");
 
   // Check the task is killed by ourselves if deadlock happends.
   // Otherwise, thread_killer should not be triggered.
-  ASSERT_NE(task_done, killed);
+  ASSERT_NE(task_done.load(), killed);
 
-  ASSERT_TRUE(task_done);
+  ASSERT_TRUE(task_done.load());
 }
diff --git a/test/test_duplex.cpp b/test/test_duplex.cpp
index 3437762..6237c1a 100644
--- a/test/test_duplex.cpp
+++ b/test/test_duplex.cpp
@@ -17,13 +17,14 @@
 #include <memory>
 #include "cubeb/cubeb.h"
 #include "common.h"
+#include <atomic>
 
 #define SAMPLE_FREQUENCY 48000
 #define STREAM_FORMAT CUBEB_SAMPLE_FLOAT32LE
 
 struct user_state_duplex
 {
-  bool seen_audio;
+  std::atomic<int> seen_audio{ 0 };
 };
 
 long data_cb_duplex(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
@@ -31,7 +32,7 @@ long data_cb_duplex(cubeb_stream * stream, void * user, const void * inputbuffer
   user_state_duplex * u = reinterpret_cast<user_state_duplex*>(user);
   float *ib = (float *)inputbuffer;
   float *ob = (float *)outputbuffer;
-  bool seen_audio = true;
+  bool seen_audio = 1;
 
   if (stream == NULL || inputbuffer == NULL || outputbuffer == NULL) {
     return CUBEB_ERROR;
@@ -42,7 +43,7 @@ long data_cb_duplex(cubeb_stream * stream, void * user, const void * inputbuffer
   long output_index = 0;
   for (long i = 0; i < nframes; i++) {
     if (ib[i] <= -1.0 && ib[i] >= 1.0) {
-      seen_audio = false;
+      seen_audio = 0;
       break;
     }
     ob[output_index] = ob[output_index + 1] = ib[i];
@@ -80,7 +81,7 @@ TEST(cubeb, duplex)
   cubeb_stream_params input_params;
   cubeb_stream_params output_params;
   int r;
-  user_state_duplex stream_state = { false };
+  user_state_duplex stream_state;
   uint32_t latency_frames = 0;
 
   r = common_init(&ctx, "Cubeb duplex example");
@@ -120,5 +121,5 @@ TEST(cubeb, duplex)
   delay(500);
   cubeb_stream_stop(stream);
 
-  ASSERT_TRUE(stream_state.seen_audio);
+  ASSERT_TRUE(stream_state.seen_audio.load());
 }
diff --git a/test/test_record.cpp b/test/test_record.cpp
index 9a65d3b..b25eb8a 100644
--- a/test/test_record.cpp
+++ b/test/test_record.cpp
@@ -16,13 +16,14 @@
 #include <memory>
 #include "cubeb/cubeb.h"
 #include "common.h"
+#include <atomic>
 
 #define SAMPLE_FREQUENCY 48000
 #define STREAM_FORMAT CUBEB_SAMPLE_FLOAT32LE
 
 struct user_state_record
 {
-  bool seen_audio;
+  std::atomic<int> seen_audio{ 0 };
 };
 
 long data_cb_record(cubeb_stream * stream, void * user, const void * inputbuffer, void * outputbuffer, long nframes)
@@ -34,10 +35,10 @@ long data_cb_record(cubeb_stream * stream, void * user, const void * inputbuffer
     return CUBEB_ERROR;
   }
 
-  bool seen_audio = true;
+  bool seen_audio = 1;
   for (long i = 0; i < nframes; i++) {
     if (b[i] <= -1.0 && b[i] >= 1.0) {
-      seen_audio = false;
+      seen_audio = 0;
       break;
     }
   }
@@ -75,7 +76,7 @@ TEST(cubeb, record)
   cubeb_stream *stream;
   cubeb_stream_params params;
   int r;
-  user_state_record stream_state = { false };
+  user_state_record stream_state;
 
   r = common_init(&ctx, "Cubeb record example");
   ASSERT_EQ(r, CUBEB_OK) << "Error initializing cubeb library";
@@ -109,6 +110,6 @@ TEST(cubeb, record)
   // user callback does not arrive in Linux, silence the error
   fprintf(stderr, "Check is disabled in Linux\n");
 #else
-  ASSERT_TRUE(stream_state.seen_audio);
+  ASSERT_TRUE(stream_state.seen_audio.load());
 #endif
 }
diff --git a/test/test_tone.cpp b/test/test_tone.cpp
index 47d9675..3cfc0b0 100644
--- a/test/test_tone.cpp
+++ b/test/test_tone.cpp
@@ -17,13 +17,14 @@
 #include <limits.h>
 #include "cubeb/cubeb.h"
 #include "common.h"
+#include <atomic>
 
 #define SAMPLE_FREQUENCY 48000
 #define STREAM_FORMAT CUBEB_SAMPLE_S16LE
 
 /* store the phase of the generated waveform */
 struct cb_user_data {
-  long position;
+  std::atomic<long> position;
 };
 
 long data_cb_tone(cubeb_stream *stream, void *user, const void* /*inputbuffer*/, void *outputbuffer, long nframes)
@@ -111,5 +112,5 @@ TEST(cubeb, tone)
   delay(500);
   cubeb_stream_stop(stream);
 
-  ASSERT_TRUE(user_data->position);
+  ASSERT_TRUE(user_data->position.load());
 }