On Wed, Oct 17, 2018 at 01:17:18PM +0200, Thomas Gleixner wrote: > On Wed, 17 Oct 2018, Peter Zijlstra wrote: > > On Wed, Oct 17, 2018 at 09:54:38AM +0000, David Laight wrote: > > > > * We should perform an IPI and flush all tlbs, > > > > * but that can deadlock->flush only current cpu: > > > > */ > > > > + preempt_disable(); > > > > __flush_tlb_all(); > > > > + preempt_enable(); > > > > > > Can it make any sense to flush the tlb with preemption enabled? > > > Surely preemption must be disabled over something else as well? > > > > This code is fishy anyway, for only doing that local invalidate. > > > > Ideally we'd never ever merge anything that only does local invalidates, > > on a global address space, that's just broken. > > A little bit late to lament about that.
For this, yes :/ But for future stuff we should really not allow such things anymore. > So should we just replace it with cpa_flush_all() ? The comment there suggests that will deadlock, supposedly because the kernel_map_page() call can happen with IRQs disabled or such. I've not deeply looked at this.
