Check pointer 'kern->accel_queue_front' for NULL before dereferencing

Pointer 'kern->accel_queue_front' returned from call to function 'acl_malloc' at line 954 may be NULL and will be dereferenced at line 964

Author: sherry-yuan

src/acl_kernel_if.cpp

@@ -958,6 +958,7 @@ int acl_kernel_if_update(const acl_device_def_autodiscovery_t &devdef,
     // Kernel IRQ is a separate thread. Need to use circular buffer to make this
     // multithread safe.
     kern->accel_queue_front = (int *)acl_malloc(kern->num_accel * sizeof(int));
+    assert(kern->accel_queue_front);
     kern->accel_queue_back = (int *)acl_malloc(kern->num_accel * sizeof(int));
 
     for (unsigned a = 0; a < kern->num_accel; ++a) {