[PATCH 0/1] x86/fpu: x86/fpu: avoid math_state_restore() without used_math() in __restore_xstate_sig()

Oleg Nesterov
2015-03-07T15:40:40Z

On 03/05, Oleg Nesterov wrote:
>
> The patch is horrible, yes. But simple, and math_state_restore/init_fpu
> are already horrible and need the cleanups.

OK, nobody liked it. How about this one for stable?

Ingo, Linus, Andy. I do agree, math_state_restore() should be called with
irqs enabled. And I was going to do this too. But this is wrong without
other changed. I hope I send them soon.

We need to remove this !tsk_used_math() code from math_state_restore().
And init_fpu() should die. Just look at __restore_xstate_sig() changed
by this patch. Why does it call init_fpu() ? We only need fpu_alloc().
fpu_finit() is pointless, we are going to overwrite fpu->state. used_math()
makes no sense at this point. user_fpu_begin() and math_state_restore()
should set this flag. And other changes.

Could you please review?

Oleg.