On Tue, 11 Jul 2023, Mark Brown wrote: > On Mon, Jul 10, 2023 at 09:34:42PM -0700, Hugh Dickins wrote: > > > I suppose I should ask you to try reverting this 0d1c81edc61e alone > > from 6.5-rc1: the consistency of your bisection implies that it will > > "fix" the issues, and it is a commit which we could drop. It makes > > me a little nervous, applying userspace-pagetable validation to kernel > > pagetables, so I don't want to drop it; and it would really be cargo- > > culting to drop it without understanding. But we could drop it. > > I did look at that, it doesn't revert cleanly by itself. ... Right, that ptep_get() wrapper on the next line came in on top. The patch to revert just 0d1c81edc61e is this: --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -703,10 +703,11 @@ struct page *vmalloc_to_page(const void if (WARN_ON_ONCE(pmd_bad(*pmd))) return NULL; - ptep = pte_offset_kernel(pmd, addr); + ptep = pte_offset_map(pmd, addr); pte = ptep_get(ptep); if (pte_present(pte)) page = pte_page(pte); + pte_unmap(ptep); return page; }
