The patch titled
Subject: mm/rmap: fix potential pte_unmap on an not mapped pte
has been added to the -mm tree. Its filename is
mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/rmap: fix potential pte_unmap on an not mapped pte
For PMD-mapped page (usually THP), pvmw->pte is NULL. For PTE-mapped THP,
pvmw->pte is mapped. But for HugeTLB pages, pvmw->pte is not mapped and
set to the relevant page table entry. So in page_vma_mapped_walk_done(),
we may do pte_unmap() for HugeTLB pte which is not mapped. Fix this by
checking pvmw->page against PageHuge before trying to do pte_unmap().
Link: https://lkml.kernel.org/r/20210127093349.39081-1-linmiaohe@xxxxxxxxxx
Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Hongxiang Lou <louhongxiang@xxxxxxxxxx>
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/rmap.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/include/linux/rmap.h~mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte
+++ a/include/linux/rmap.h
@@ -213,7 +213,8 @@ struct page_vma_mapped_walk {
static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
{
- if (pvmw->pte)
+ /* HugeTLB pte is set to the relevant page table entry without pte_mapped. */
+ if (pvmw->pte && !PageHuge(pvmw->page))
pte_unmap(pvmw->pte);
if (pvmw->ptl)
spin_unlock(pvmw->ptl);
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-rmap-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
mm-page_owner-use-helper-function-zone_end_pfn-to-get-end_pfn.patch
mm-fix-potential-pte_unmap_unlock-pte-error.patch
mm-hugetlb-fix-potential-double-free-in-hugetlb_register_node-error-path.patch
mm-hugetlb-avoid-unnecessary-hugetlb_acct_memory-call.patch
mm-hugetlb-use-helper-huge_page_order-and-pages_per_huge_page.patch
mm-hugetlb-fix-use-after-free-when-subpool-max_hpages-accounting-is-not-enabled.patch
mm-workingsetc-avoid-unnecessary-max_nodes-estimation-in-count_shadow_nodes.patch
z3fold-remove-unused-attribute-for-release_z3fold_page.patch
z3fold-simplify-the-zhdr-initialization-code-in-init_z3fold_page.patch
mm-compaction-remove-duplicated-vm_bug_on_page-pagelocked.patch
hugetlbfs-remove-useless-bug_oninode-in-hugetlbfs_setattr.patch
hugetlbfs-use-helper-macro-default_hstate-in-init_hugetlbfs_fs.patch
hugetlbfs-correct-obsolete-function-name-in-hugetlbfs_read_iter.patch
hugetlbfs-remove-meaningless-variable-avoid_reserve.patch
hugetlbfs-make-hugepage-size-conversion-more-readable.patch
hugetlbfs-correct-some-obsolete-comments-about-inode-i_mutex.patch
mm-memory_hotplug-use-helper-function-zone_end_pfn-to-get-end_pfn.patch
mm-rmap-correct-some-obsolete-comments-of-anon_vma.patch
mm-zsmallocc-convert-to-use-kmem_cache_zalloc-in-cache_alloc_zspage.patch
