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| author | Baolin Wang <baolin.wang@linux.alibaba.com> | 2024-12-19 08:30:08 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-12-31 02:59:09 +0100 |
| commit | d0e6983a6d1719738cf8d13982a68094f0a1872a (patch) | |
| tree | 3d0c0a8f384da2cbeb0e5c5c724802cfb67d2699 | |
| parent | percpu: remove intermediate variable in PERCPU_PTR() (diff) | |
| download | linux-d0e6983a6d1719738cf8d13982a68094f0a1872a.tar.xz linux-d0e6983a6d1719738cf8d13982a68094f0a1872a.zip | |
mm: shmem: fix incorrect index alignment for within_size policy
With enabling the shmem per-size within_size policy, using an incorrect
'order' size to round_up() the index can lead to incorrect i_size checks,
resulting in an inappropriate large orders being returned.
Changing to use '1 << order' to round_up() the index to fix this issue.
Additionally, adding an 'aligned_index' variable to avoid affecting the
index checks.
Link: https://lkml.kernel.org/r/77d8ef76a7d3d646e9225e9af88a76549a68aab1.1734593154.git.baolin.wang@linux.alibaba.com
Fixes: e7a2ab7b3bb5 ("mm: shmem: add mTHP support for anonymous shmem")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/shmem.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index f6fb053ac50d..dec659e84562 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1689,6 +1689,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode, unsigned long mask = READ_ONCE(huge_shmem_orders_always); unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size); unsigned long vm_flags = vma ? vma->vm_flags : 0; + pgoff_t aligned_index; bool global_huge; loff_t i_size; int order; @@ -1723,9 +1724,9 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode, /* Allow mTHP that will be fully within i_size. */ order = highest_order(within_size_orders); while (within_size_orders) { - index = round_up(index + 1, order); + aligned_index = round_up(index + 1, 1 << order); i_size = round_up(i_size_read(inode), PAGE_SIZE); - if (i_size >> PAGE_SHIFT >= index) { + if (i_size >> PAGE_SHIFT >= aligned_index) { mask |= within_size_orders; break; } |