The patch titled
Subject: mm/memory.c: fix potential pte_unmap_unlock pte error
has been added to the -mm tree. Its filename is
mm-memoryc-fix-potential-pte_unmap_unlock-pte-error.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-memoryc-fix-potential-pte_unmap_unlock-pte-error.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-memoryc-fix-potential-pte_unmap_unlock-pte-error.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/memory.c: fix potential pte_unmap_unlock pte error
If all pte entry is none in 'non-create' case, we would break the loop with
pte unchanged. Then the wrong pte - 1 would be passed to pte_unmap_unlock.
This is a theoretical issue which may not be a real bug. So it's not worth
cc stable.
Link: https://lkml.kernel.org/r/20210205081925.59809-1-linmiaohe@xxxxxxxxxx
Fixes: aee16b3cee27 ("Add apply_to_page_range() which applies a function to a pte range")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Ian Pratt <ian.pratt@xxxxxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/memory.c~mm-memoryc-fix-potential-pte_unmap_unlock-pte-error
+++ a/mm/memory.c
@@ -2382,18 +2382,18 @@ static int apply_to_pte_range(struct mm_
pte_fn_t fn, void *data, bool create,
pgtbl_mod_mask *mask)
{
- pte_t *pte;
+ pte_t *pte, *mapped_pte;
int err = 0;
spinlock_t *ptl;
if (create) {
- pte = (mm == &init_mm) ?
+ mapped_pte = pte = (mm == &init_mm) ?
pte_alloc_kernel_track(pmd, addr, mask) :
pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
} else {
- pte = (mm == &init_mm) ?
+ mapped_pte = pte = (mm == &init_mm) ?
pte_offset_kernel(pmd, addr) :
pte_offset_map_lock(mm, pmd, addr, &ptl);
}
@@ -2416,7 +2416,7 @@ static int apply_to_pte_range(struct mm_
arch_leave_lazy_mmu_mode();
if (mm != &init_mm)
- pte_unmap_unlock(pte-1, ptl);
+ pte_unmap_unlock(mapped_pte, ptl);
return err;
}
_
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-simplify-the-vm_bug_on-condition-in-pmdp_huge_clear_flush.patch
mm-pgtable-genericc-optimize-the-vm_bug_on-condition-in-pmdp_huge_clear_flush.patch
mm-memoryc-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-hugetlb-fix-some-comment-typos.patch
mm-remove-unused-return-value-of-set_huge_zero_page.patch
hugetlb_cgroup-use-helper-pages_per_huge_page-in-hugetlb_cgroup.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
mm-mempolicy-use-helper-range_in_vma-in-queue_pages_test_walk.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
hugetlbfs-fix-some-comment-typos.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-rmap-remove-unneeded-semicolon-in-page_not_mapped.patch
mm-rmap-fix-obsolete-comment-in-__page_check_anon_rmap.patch
mm-rmap-use-page_not_mapped-in-try_to_unmap.patch
mm-rmap-correct-obsolete-comment-of-page_get_anon_vma.patch
mm-zsmallocc-convert-to-use-kmem_cache_zalloc-in-cache_alloc_zspage.patch
mm-zsmallocc-use-page_private-to-access-page-private.patch
