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Re: V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
On 07/13/2018 02:55 PM, Jeff Law wrote:
> On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
>> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>>> This will be used by CET run-time control.
>>>>
>>>> [BZ #22563]
>>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>>> Likewise.
>>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>>> to feature_1.
>>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>>
>>> Here is the updated patch to add feature_1 to tcbhead_t and
>>> introduce macros for CET enabling. OK for master?
>>
>> Fix the typo-prone macro API and post a v3 please.
>>
>> Thank you.
> Umm, has this been tested with the sanitizers? I thought they used that
> field.
The size of tcbhead_t has not changed, which is something that might impact
the santiziers.
But now that you mention it, why do I vaguely remember a conversation about
the santizers using the reserved bytes as storage for themselves?
Is that what you are talking about?
HJ, could you look into this please?
I think the sanitizers are not within their rights to use any bytes in the
tcbhead_t structure, particularly reserved bytes. We should coordinate with
them, but that should not stop the acceptance of this patch in 2.28.
Cheers,
Carlos.