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I think > > the memdesc would also need to follow a SLAB_TYPESAFE_BY_RCU design as > > well. > > I haven't quite figured out if _all_ memdescs need to be TYPESAFE_BY_RCU > or only the ones which either have refcounts or are otherwise > migratable. Anything that de-references page->memdesc under RCU using the re-check flow you outlined has to also use TYPESAFE_BY_RCU for the page->memdesc allocation to avoid UAF under a RCU read side critical section. Likely it doesn't make sense to RCU de-reference page->memdesc for anything other than incrementing a refcount. Jason