[Linux-ia64] Re: switch_mm race condition with Ingo's scheduler

[Erich Focht <efocht@ess.nec.de>]

> Also, I think it's sufficient to
> call delayed_flush_tlb() in get_new_mmu_context(), as we just need to
> make sure that the TLB does get flushed before.  Or did this not work
> for some reason?

But then other processors would continue using the old TLBs maybe of
tasks which died. The problem is that we need to do a TLB flush on all
CPUs when wrapping around the context. Otherwise we might reuse the context
number of a recently exited process and on other CPUs some of its TLB entries
may survive until the new task switches CPUs. Hard to debug, probably...

Regards,
Erich