[revert request for commit 9fff2fa] Re: [git pull] signals pile 3

[Al Viro]

On Sun, Oct 14, 2012 at 08:24:03PM +0100, Al Viro wrote:

> Russell, could you recall what those had been about?  I'm not sure if that
> had been oopsable that far back (again, oops scenario is userland stack
> page getting swapped out before we get to start_thread(), leading to
> direct read from an absent page in start_thread() by plain ldr, without
> anything in exception table about that insn), but it looks very odd
> regardless of that problem.

BTW, arm64 has copied that logics, so it also seems to be unsafe and very
odd - there we definitely have only ELF to cope with.  arm64 folks Cc'd...