The latest versions of IDF include a new esp_timer library that seems to be incrementing the task notification values in unexpected places depending on other tasks in operation.

This causes task blocking to fail in client operations leading to exceptions and crashing.

This is a workaround for this situation and will need to be reworked properly in the future.

src/NimBLERemoteDescriptor.cpp

@@ -137,7 +137,8 @@ std::string NimBLERemoteDescriptor::readValue() {
 
     int rc = 0;
     int retryCount = 1;
-    ble_task_data_t taskData = {this, xTaskGetCurrentTaskHandle(),0, &value};
+    TaskHandle_t cur_task = xTaskGetCurrentTaskHandle();
+    ble_task_data_t taskData = {this, cur_task, 0, &value};
 
     do {
         rc = ble_gattc_read_long(pClient->getConnId(), m_handle, 0,
@@ -149,6 +150,10 @@ std::string NimBLERemoteDescriptor::readValue() {
             return value;
         }
 
+#ifdef ulTaskNotifyValueClear
+        // Clear the task notification value to ensure we block
+        ulTaskNotifyValueClear(cur_task, ULONG_MAX);
+#endif
         ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
         rc = taskData.rc;
 
@@ -289,7 +294,8 @@ bool NimBLERemoteDescriptor::writeValue(const uint8_t* data, size_t length, bool
         return (rc == 0);
     }
 
-    ble_task_data_t taskData = {this, xTaskGetCurrentTaskHandle(), 0, nullptr};
+    TaskHandle_t cur_task = xTaskGetCurrentTaskHandle();
+    ble_task_data_t taskData = {this, cur_task, 0, nullptr};
 
     do {
         if(length > mtu) {
@@ -310,6 +316,10 @@ bool NimBLERemoteDescriptor::writeValue(const uint8_t* data, size_t length, bool
             return false;
         }
 
+#ifdef ulTaskNotifyValueClear
+        // Clear the task notification value to ensure we block
+        ulTaskNotifyValueClear(cur_task, ULONG_MAX);
+#endif
         ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
         rc = taskData.rc;