On Sat, Dec 15, 2018 at 04:01:30PM +0100, Richard Weinberger wrote:
> The page migration code assumes that a page with PG_private
> set has its page count elevated by 1.
> UBIFS never did this and therefore the migration code was unable
> to migrate some pages owned by UBIFS.
> The lead to situations where the CMA memory allocator failed to
> allocate memory.
>
> Fix this by using get/put_page when changing PG_private.
Looks good to me.
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Cc: zhangjun <openzhangj@xxxxxxxxx>
> Fixes: 4ac1c17b2044 ("UBIFS: Implement ->migratepage()")
It is fair to reference the commit here. But I believe the bug itself
predates the commit and relevant not only for migration.
We might make it clear in the commit message.
--
Kirill A. Shutemov
