Re: [PATCH] x86/signals: Fix save/restore signal stack to correctly support sigset_t

[Al Viro]

On Thu, Nov 19, 2020 at 02:11:33PM -0800, Walt Drummond wrote:
> The macro unsafe_put_sigmask() only handles the first 64 bits of the
> sigmask_t, which works today.  However, if the definition of the
> sigset_t structure ever changed,

... existing userland would get fucked over, since sigset_t is
present in user-visible data structures.  Including the ones
we are using that thing for - struct rt_sigframe, for starters.

Layout of those suckers is very much cast in stone.  We *can't*
change it, no matter what we do kernel-side.

NAKed-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>