On Wed, Aug 23, 2023 at 07:16:52PM +0100, Mark Brown wrote: > On Wed, Aug 23, 2023 at 06:40:40PM +0100, Szabolcs Nagy wrote: > > i don't know if we can allow disabled gcs thread creation with locked > > gcs state. (i can see arguments both ways, so further prctl flag may > > be needed which may be another divergence from x86) > > I think that if we do add a new flag that'd just be new functionality, > the divergence would be in allowing configuration via clone3() rather > than the flag. TBH I'm not sure I see a use case for locking but > providing a mechanism for getting out of the lock, that seems very > questionable. You are right, once the configuration is locked a plain clone() or clone3() without a GCS pointer should be rejected. Is there a use-case for the unlocked configuration to allow disabling the GCS implicitly via a clone syscall? If we go for extending clone3, I wonder whether we should also introduce a sigaltstack2/3 ;). I haven't checked what the current patches do and won't have time until early September (on holiday from the end of today). -- Catalin
