[tlb]

The kernel programmer did, in this story.

An example of such an information leak is:

  struct foo {
    int a;
    char b;
  }

  void send_foo_01() {
    foo x {0, 1};
    write(fd, &x, sizeof(foo));
  }

which sends 3 bytes of the contents of the stack memory over the network, for almost every compiler except the one in the story. Running in a kernel, that could contain secrets.

[EpicEng]

Sorry, my mistake; yes, the kernel dev is now relying on the compiler to zero out those three bytes. I understand the decision to change this in the compiler, but I think the "fix" would have been to memset in the kernel code. I'd be surprised if they didn't do that, but maybe they can reasonably assume they'll never use another compiler to build the Windows kernel.