[PATCH] mm: Check we have the right vma in __access_remote_vm()

[KOSAKI Motohiro]

> In __access_remote_vm() we need to check that we have found the right
> vma, not the following vma, before we try to access it. Otherwise we
> might call the vma's access routine with an address which does not
> fall inside the vma.
> 
> Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
> ---
>  mm/memory.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 9da8cab..ce999ca 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3678,7 +3678,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
>  			 */
>  #ifdef CONFIG_HAVE_IOREMAP_PROT
>  			vma = find_vma(mm, addr);
> -			if (!vma)
> +			if (!vma || vma->vm_start > addr)
>  				break;
>  			if (vma->vm_ops && vma->vm_ops->access)
>  				ret = vma->vm_ops->access(vma, addr, buf,

Looks good to me.
	Reviewed-by: KOSAKI Motohiro <kosaki.motohiro at jp.fujitsu.com>