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| author | Miaohe Lin <linmiaohe@huawei.com> | 2021-02-24 21:04:42 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-24 22:38:30 +0100 |
| commit | 8abb50c76b484e8d8dc355c092170c37b5f832f5 (patch) | |
| tree | 05b1c55fb1361547b339f538099ddf4e9b71cdf4 /mm/memory.c | |
| parent | mm/pgtable-generic.c: optimize the VM_BUG_ON condition in pmdp_huge_clear_flu... (diff) | |
| download | linux-8abb50c76b484e8d8dc355c092170c37b5f832f5.tar.xz linux-8abb50c76b484e8d8dc355c092170c37b5f832f5.zip | |
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@huawei.com
Fixes: aee16b3cee27 ("Add apply_to_page_range() which applies a function to a pte range")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ian Pratt <ian.pratt@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/memory.c b/mm/memory.c index 83e1bcf7a669..ef4e10c60b5f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2394,18 +2394,18 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 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); } @@ -2428,7 +2428,7 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, arch_leave_lazy_mmu_mode(); if (mm != &init_mm) - pte_unmap_unlock(pte-1, ptl); + pte_unmap_unlock(mapped_pte, ptl); return err; } |