On Mon, Nov 21, 2016 at 1:21 PM, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Mon, Nov 21, 2016 at 10:26 AM, H. Peter Anvin <h...@zytor.com> wrote: >> On 11/21/16 10:00, Linus Torvalds wrote: >>> >>> I'd much rather we go back to just making the "cs" entry explicitly >>> 16-bit, and have a separate padding entry, the way we used to long >>> long ago. >>> >> >> I would agree 100% with this. > > We _used_ to do it like this in some places (signal stack, other places): > > unsigned short cs, __csh;
I'm testing a patch to do exactly this. I didn't bother with the fancy anonymous union stuff because I don't see any great reason that anything needs to write the high bits. Amusingly, grsecurity seems to contain a fix for one instance of this bug on x86_32 and one instance on x86_64 (!). --Andy
