Re: [PATCH] powerpc: Update AT_HWCAP2 bits

[Florian Weimer <fweimer at redhat dot com>]

On 11/21/2017 12:46 PM, Andreas Schwab wrote:
> On Nov 21 2017, Florian Weimer <fweimer@redhat.com> wrote:
>
> > On 11/21/2017 12:21 PM, Andreas Schwab wrote:
> > > On Nov 21 2017, "Tulio Magno Quites Machado Filho" <tuliom@linux.vnet.ibm.com> wrote:
> > >
> > > > This patch is changing an internal structure.
> > > > Could you elaborate why you think this is a problem?
> > >
> > > _rtld_global_ro is part of the ld.so interface.
> >
> > Are you suggesting that we cannot change GLIBC_PRIVATE ABIs on a release
> > branch?
>
> You will need to restart all running processes to avoid getting
> conflicts after such an update.

I think _rtld_global_ro is fairly harmless in this regard because there 
is only a small window during process startup, before libc.so.6 is 
loaded.  So this will only affect processes started during the update 
(and perhaps dlmopen).

Other GLIBC_PRIVATE changes are far more invasive because they affect 
anything which does a late dlopen (which can happen an arbitrary time 
span after the update, of course).

Thanks,
Florian