From d628284548038dc6d48e374f4466aaa1e7e69aa5 Mon Sep 17 00:00:00 2001
From: David Reid <mackron@gmail.com>
Date: Sat, 4 Jan 2025 09:07:20 +1000
Subject: [PATCH] Fix a thread-safety error with `ma_device_start/stop()`.

Public issue https://github.com/mackron/miniaudio/issues/919.
---
 miniaudio.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/miniaudio.h b/miniaudio.h
index 0c4a120a..67733480 100644
--- a/miniaudio.h
+++ b/miniaudio.h
@@ -42520,6 +42520,14 @@ MA_API ma_result ma_device_start(ma_device* pDevice)
 
     ma_mutex_lock(&pDevice->startStopLock);
     {
+        /*
+        We need to check again if the device is in a started state because it's possible for one thread to have started the device
+        while another was waiting on the mutex.
+        */
+        if (ma_device_get_state(pDevice) == ma_device_state_started) {
+            return MA_SUCCESS;  /* Already started. */
+        }
+
         /* Starting and stopping are wrapped in a mutex which means we can assert that the device is in a stopped or paused state. */
         MA_ASSERT(ma_device_get_state(pDevice) == ma_device_state_stopped);
 
@@ -42580,6 +42588,14 @@ MA_API ma_result ma_device_stop(ma_device* pDevice)
 
     ma_mutex_lock(&pDevice->startStopLock);
     {
+        /*
+        We need to check again if the device is in a stopped state because it's possible for one thread to have stopped the device
+        while another was waiting on the mutex.
+        */
+        if (ma_device_get_state(pDevice) == ma_device_state_stopped) {
+            return MA_SUCCESS;  /* Already stopped. */
+        }
+
         /* Starting and stopping are wrapped in a mutex which means we can assert that the device is in a started or paused state. */
         MA_ASSERT(ma_device_get_state(pDevice) == ma_device_state_started);