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    Subject[PATCH 5.15 540/779] mm/mmap.c: fix missing call to vm_unacct_memory in mmap_region
    Date
    From: Miaohe Lin <linmiaohe@huawei.com>

    [ Upstream commit 7f82f922319ede486540e8746769865b9508d2c2 ]

    Since the beginning, charged is set to 0 to avoid calling vm_unacct_memory
    twice because vm_unacct_memory will be called by above unmap_region. But
    since commit 4f74d2c8e827 ("vm: remove 'nr_accounted' calculations from
    the unmap_vmas() interfaces"), unmap_region doesn't call vm_unacct_memory
    anymore. So charged shouldn't be set to 0 now otherwise the calling to
    paired vm_unacct_memory will be missed and leads to imbalanced account.

    Link: https://lkml.kernel.org/r/20220618082027.43391-1-linmiaohe@huawei.com
    Fixes: 4f74d2c8e827 ("vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces")
    Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    mm/mmap.c | 1 -
    1 file changed, 1 deletion(-)

    diff --git a/mm/mmap.c b/mm/mmap.c
    index 6bb553ed5c55..031fca1a7c65 100644
    --- a/mm/mmap.c
    +++ b/mm/mmap.c
    @@ -1878,7 +1878,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,

    /* Undo any partial mapping done by a device driver. */
    unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
    - charged = 0;
    if (vm_flags & VM_SHARED)
    mapping_unmap_writable(file->f_mapping);
    free_vma:
    --
    2.35.1


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