title: So malloc doesn't invoke any syscall?
body: <p>Related code:</p>
  
  <pre><code>  write(-1, "test", sizeof("test"));
    void * p = malloc(1024);
    void * p2 = malloc(510);
    write(-1, "hi", sizeof("hi"));
  </code></pre>
  
  <p>Related strace output:</p>
  
  <pre><code>write(4294967295, "test\0", 5)          = -1 EBADF (Bad file descriptor)
  brk(0)                                  = 0x601000
  brk(0x622000)                           = 0x622000
  write(4294967295, "hi\0", 3)            = -1 EBADF (Bad file descriptor)
  </code></pre>
  
  <p>I'm surprised such low level operation doesn't involve syscall?</p>