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

From: Dave Hansen
Date: Fri Jul 29 2016 - 13:51:00 EST


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