svn commit: r280780 - head/sys/amd64/amd64

[Konstantin Belousov]

On Sat, Mar 28, 2015 at 09:02:20AM +0000, Konstantin Belousov wrote:
> Author: kib
> Date: Sat Mar 28 09:02:19 2015
> New Revision: 280780
> URL: https://svnweb.freebsd.org/changeset/base/280780
> 
> Log:
>   The #ss fault handler erronously does not check for the fault
>   originated from the return to usermode. #ss must be handled same as
>   #np.

Note that this is an omission in r275833.  I fixed the wrong gs base for
#ss and #np, but failed to note the lack of required check for iretd
faulting on the way to usermode for #ss.

So this is not a 'security' issue, only the local DoS: kernel excessively
panics instead of delivering trap to userspace.