On Wed, Aug 23, 2023 at 01:51:35PM +0100, Mark Brown wrote:

On Wed, Aug 23, 2023 at 11:09:59AM +0100, Szabolcs Nagy wrote:

quoted

The 08/22/2023 18:53, Mark Brown wrote:

quoted

My sense is that they deployment story is going to be smoother with
defaults being provided since it avoids dealing with the issue of what
to do if userspace creates a thread without a GCS in a GCS enabled
process but like I say I'd be totally happy to extend clone3().  I will
put some patches together for that (probably once the x86 stuff lands).
Given the size of this series it might be better split out for
manageability if nothing else.

quoted

i would make thread without gcs to implicitly disable gcs, since
that's what's bw compat with clones outside of libc (the libc can
guarantee gcs allocation when gcs is enabled).

That'd create a pretty substantial divergence with the x86 patches if
they land this time around, there's not enough time to rework them now -
I suppose it'd mainly bite people implementing libc type stuff but
still, doesn't feel great.

I don't mind the divergence in this area if the libc folks are ok with
it. x86 can eventually use the clone3() interface if they want more
flexibility, they'll just have to continue supporting the old one. I
think we already diverge around the prctl().

-- 
Catalin