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SubjectRe: [Patch]Fix an error in copy_page_range
Zou Nan hai wrote:
> Hi,
>
> There is a bug in copy_page_range in current 2.6.11-rc1 with 4 level
> page table change. copy_page_range do a continue without adding pgds and
> addr when pgd_none(*src_pgd) or pgd_bad(*src_pgd).
>
> I think it's wrong in logic, copy_page_range will run into infinite loop
> when when pgd_none(*src_pgd) or pgd_bad(*src_pgd).
>
> Although maybe this bug does not break anything currently...,
>
>
> Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
>
> --- a/mm/memory.c 2005-01-21 01:21:18.000000000 +0800
> +++ b/mm/memory.c 2005-01-21 04:49:13.000000000 +0800
> @@ -442,17 +442,18 @@ int copy_page_range(struct mm_struct *ds
> if (next > end || next <= addr)
> next = end;
> if (pgd_none(*src_pgd))
> - continue;
> + goto next_pgd;
> if (pgd_bad(*src_pgd)) {
> pgd_ERROR(*src_pgd);
> pgd_clear(src_pgd);
> - continue;
> + goto next_pgd;
> }
> err = copy_pud_range(dst, src, dst_pgd, src_pgd,
> vma, addr, next);
> if (err)
> break;
>
> +next_pgd:
> src_pgd++;
> dst_pgd++;
> addr = next;
>
>
>

This looks right to me. Andrew and/or Linus, did this get picked up?


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