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

From	Dave Hansen <dave.hansen@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU
Date	2016-07-29 20:00 +0200
Message-ID	<s0keK-7S4-13@gated-at.bofh.it> (permalink)
References	<s0iZj-763-3@gated-at.bofh.it> <s0iZj-763-13@gated-at.bofh.it> <s0jVo-7KZ-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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.

Thread

[PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Dave Hansen <dave@sr71.net> - 2016-07-29 18:40 +0200
  Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Andy Lutomirski <luto@amacapital.net> - 2016-07-29 19:40 +0200
    Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Dave Hansen <dave.hansen@intel.com> - 2016-07-29 20:00 +0200
      Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Andy Lutomirski <luto@amacapital.net> - 2016-07-29 21:50 +0200
  Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Vlastimil Babka <vbabka@suse.cz> - 2016-08-01 16:50 +0200
    Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Dave Hansen <dave@sr71.net> - 2016-08-01 17:10 +0200
      Re: [PATCH 08/10] x86, pkeys: default to a restrictive init PKRU Vlastimil Babka <vbabka@suse.cz> - 2016-08-02 10:30 +0200

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