Kernel buffer overflow exposes iPhone 11 Pro to radio based attacks

[Walter Bright]

On 12/4/2020 1:24 AM, Timon Gehr wrote:
> The only reason why `HLT` terminates execution of userspace code is that such 
> code does not have sufficient permissions to execute the instruction; in the 
> kernel, it would not do much.

The compiler actually was changed to generate a UD2 instruction (0x0F0B) at the 
suggestion of (if I remember correctly) Iain.

   https://www.felixcloutier.com/x86/ud

which raises the invalid opcode exception.

   https://github.com/dlang/dmd/blob/master/src/dmd/backend/cod2.d#L5723