Hi,

On Thu, Aug 09, 2018 at 08:28:17PM -0400, zhouxianrong wrote:
> From: zhouxianrong <zhouxianr...@huawei.com>
> 
> The last partial object in last subpage of zspage should not be linked
> in allocation list. Otherwise it could trigger BUG_ON explicitly at
> function zs_map_object. But it happened rarely.

Could you be more specific? What case did you see the problem?
Is it a real problem or one founded by review?

Thanks.

> 
> Signed-off-by: zhouxianrong <zhouxianr...@huawei.com>
> ---
>  mm/zsmalloc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 8d87e973a4f5..24dd8da0aa59 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1040,6 +1040,8 @@ static void init_zspage(struct size_class *class, 
> struct zspage *zspage)
>                        * Reset OBJ_TAG_BITS bit to last link to tell
>                        * whether it's allocated object or not.
>                        */
> +                     if (off > PAGE_SIZE)
> +                             link -= class->size / sizeof(*link);
>                       link->next = -1UL << OBJ_TAG_BITS;
>               }
>               kunmap_atomic(vaddr);
> -- 
> 2.13.6
> 

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