On Mon, 9 Jun 2014, Vladimir Davydov wrote: > The whole function (unfreeze_partials) is currently called with irqs > off, so this is effectively a no-op. I guess we can restore irqs here > though. We could move the local_irq_save from put_cpu_partial() into unfreeze_partials(). > If we just freed the last slab of the cache and then get preempted > (suppose we restored irqs above), nothing will prevent the cache from > destruction, which may result in use-after-free below. We need to be > more cautious if we want to call for page allocator with preemption and > irqs on. Hmmm. Ok. > > However, I still don't understand what's the point in it. We *already* > call discard_slab with irqs disabled, which is harder, and it haven't > caused any problems AFAIK. Moreover, even if we enabled preemption/irqs, > it wouldn't guarantee that discard_slab would always be called with > preemption/irqs on, because the whole function - I mean kmem_cache_free > - can be called with preemption/irqs disabled. > > So my point it would only complicate the code. Ok. Acked-by: Christoph Lameter <cl@xxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>