> Imagine that some brilliant lightweight threading library does: > > - set GS to nonzero (by whatever means -- arch_prctl(ARCH_SET_GS, > whatever) on a pre-IVB host followed by migration, some modify_ldt > garbage, simple bloody-mindedness, whatever);
Migration is only possible when the CPUID flags match. > - WRGSBASE > - Use GS for a bit > > This will work most of the time until it gets unlucky with preemption. As soon as a kernel thread or something else schedules the value will be lost. > And yes, runtime library authors really do mess up in amazing ways. > > It's an issue. It needs conscious design. Ok. So your only objection is the order of the context switch updates? -Andi -- [email protected] -- Speaking for myself only.
