Has cudaMalloc changed to be asynchronous?

I've read in other places that cudaMalloc will synchronize across kernels. (e.g. will cudaMalloc synchronize host and device?) However, I just tested this code out and based on what I'm seeing in the visual profiler, it seems like cudaMalloc is not synchronizing. if you add cudaFree into the loop, that does synchronize. I'm using CUDA 7.5. Does anyone know if cudaMalloc changed its behavior? Or am I missing some subtlety? Thanks very much!

__global__ void slowKernel()
{
  float input = 5;
  for( int i = 0; i < 1000000; i++ ){
    input = input * .9999999;
  }
}

__global__ void fastKernel()
{
  float input = 5;
  for( int i = 0; i < 100000; i++ ){
    input = input * .9999999;
  }
}

void mallocSynchronize(){
  cudaStream_t stream1, stream2;
  cudaStreamCreate( &stream1 );
  cudaStreamCreate( &stream2 );
  slowKernel <<<1, 1, 0, stream1 >>>();
  int *dev_a = 0;
  for( int i = 0; i < 10; i++ ){
    cudaMalloc( &dev_a, 4 * 1024 * 1024 );
    fastKernel <<<1, 1, 0, stream2 >>>();
    // cudaFree( dev_a ); // If you uncomment this, the second fastKernel launch will wait until slowKernel completes
  }
}