Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU

On Fri, Jul 29, 2016 at 10:50 AM, Dave Hansen [off-list ref] wrote:

On 07/29/2016 10:29 AM, Andy Lutomirski wrote:

quoted

quoted

quoted

In the end, this ensures that threads which do not know how to
manage their own pkey rights can not do damage to data which is
pkey-protected.

I think you missed the fpu__clear() caller in kernel/fpu/signal.c.

ISTM it might be more comprehensible to change fpu__clear in general
and then special case things you want to behave differently.

The code actually already patched the generic fpu__clear():

        fpu__clear() ->
        copy_init_fpstate_to_fpregs() ->
        copy_init_pkru_to_fpregs()

So I think it hit the case you are talking about.

Whoops, missed that.

-- 
Andy Lutomirski
AMA Capital Management, LLC