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 czg9Dwcs 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>> function already takes. > > I don't understand how a node ID can change even after the folio has > been freed. I don't think this patch is wrong, but I don't think I agree with you in the current code base. > there's actually a bug here that's being fixed. Strictly speaking, it can be seen as a benign UAF. It works, because 1. folio->flags happens to be the same as page->flags, 2. folio/page nid is stored in the ->flags and never changed. In memdesc world, after a folio is freed, I assume folio->flags would be zeroed since struct folio is freed and calling folio_nid() on a freed folio would give a bogus result (yeah, it can be mitigated by not zeroing node field and each node has its own struct folio pool, but that makes folio_nid() implementation dependent). IMHO, this patch is still worth getting in. --=20 Best Regards, Yan, Zi