On Mon, Oct 17, 2016 at 01:57:06PM -0700, Andy Lutomirski wrote:
> Dave and/or Yu-cheng: didn't one of you have some code to allow a user
> xstate buffer to be filled from the copy in kernel memory? If we did
> that, we could avoid this mess entirely.
In copy_fpstate_to_sigframe() (arch/x86/kernel/fpu/signal.c), the
assumption was we have lazy fpu:
if (fpregs_active() || we want an #NM exception)
copy kernel buffer to user buffer;
But this is not the true anymore. Or do you mean something else?