Re: PING^2: [PATCH 0/2] nptl: Update struct pthread_unwind_buf

[Carlos O'Donell <carlos at redhat dot com>]

On 02/21/2018 07:33 AM, H.J. Lu wrote:
> On Thu, Feb 15, 2018 at 12:02 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Feb 9, 2018 at 7:24 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Fri, Feb 9, 2018 at 6:33 AM, Florian Weimer <fweimer@redhat.com> wrote:
>>>> On 02/09/2018 03:13 PM, H.J. Lu wrote:
>>>>>
>>>>> I built glibc master with gcc-8.0.1 -mcet -fcf-protection.  Some object
>>>>> files do get CET marker as expected.  But static executable isn't:
>>>>
>>>>
>>>> I said static libraries.  If I compile this code (based on the example from
>>>> the manual page) on Fedora rawhide:
>>>>
>>>
>>> Glibc never provides binary compatibility with static libraries.  My suggestions
>>> are
>>>
>>> 1. Recompile static libraries after CET is enabled in glibc.  Or
>>> 2. Don't compile static libraries with CET.
>>>
>>> BTW, we don't have space to save shadow stack register with existing
>>> cancel buf.
>>>
>>
>> PING:
>>
>> https://sourceware.org/ml/libc-alpha/2018-02/msg00290.html
>> https://sourceware.org/ml/libc-alpha/2018-02/msg00291.html
>>
> 
> PING.
 
These patches are pending the conclusion of the discussion that the
shadow stack pointer does not need to be restored in the unwinding
use case, and need only be placed in such a location that if it is
written it writes within the size of the existing truncated unwind
buffer.

Please see:
https://www.sourceware.org/ml/libc-alpha/2018-02/msg00679.html

-- 
Cheers,
Carlos.