remove set_fs calls from the exec and coredump code v2

[Eric W. Biederman]

Christoph Hellwig <hch at lst.de> writes:

> Hi all,
>
> this series gets rid of playing with the address limit in the exec and
> coredump code.  Most of this was fairly trivial, the biggest changes are
> those to the spufs coredump code.
>
> Changes since v1:
>  - properly spell NUL
>  - properly handle the compat siginfo case in ELF coredumps

Quick question is exec from a kernel thread within the scope of what you
are looking at?

There is a set_fs(USER_DS) in flush_old_exec whose sole purpose appears
to be to allow exec from kernel threads.  Where the kernel threads
run with set_fs(KERNEL_DS) until they call exec.

Eric