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 QEUVj3cr 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moved huge zero PMDs must remain special so > vm_normal_page_pmd() continues to treat them as special mappings. > > move_pages_huge_pmd() currently reconstructs the destination PMD in the > huge zero page branch, which drops PMD state such as pmd_special() on > architectures with CONFIG_ARCH_HAS_PTE_SPECIAL. As a result, > vm_normal_page_pmd() can treat the moved huge zero PMD as a normal page > and corrupt its refcount. > > Instead of reconstructing the PMD from the folio, derive the destination > entry from src_pmdval after pmdp_huge_clear_flush(), then handle the PMD > metadata the same way move_huge_pmd() does for moved entries by marking > it soft-dirty and clearing uffd-wp. > > Fixes: d82d09e48219 ("mm/huge_memory: mark PMD mappings of the huge zero folio special") > Cc: stable@vger.kernel.org > Signed-off-by: Chris Down > --- > mm/huge_memory.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index fed57951a7cd..8166b5e871ad 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2794,7 +2794,8 @@ int move_pages_huge_pmd(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, pm > _dst_pmd = pmd_mkwrite(pmd_mkdirty(_dst_pmd), dst_vma); > } else { > src_pmdval = pmdp_huge_clear_flush(src_vma, src_addr, src_pmd); > - _dst_pmd = folio_mk_pmd(page_folio(src_page), dst_vma->vm_page_prot); > + _dst_pmd = move_soft_dirty_pmd(src_pmdval); > + _dst_pmd = clear_uffd_wp_pmd(_dst_pmd); I'm confused as to what's going on here, it seems like the 2/3 is simply updating the 1/3 with a different fixes? I agree with David that just moving it is probably completely fine, so I think this should be the only actual patch you need, and you can just Fixes: e3981db444a0 with it? Then make this a v3 series with 2 patches this + the test right (but maybe best not backport the test :)? > } > set_pmd_at(mm, dst_addr, dst_pmd, _dst_pmd); > > -- > 2.51.2 > > >