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 <c...@linux.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
