On Mon, Nov 26, 2018 at 03:26:34PM -0800, Hugh Dickins wrote:
> Huge tmpfs testing reminds us that there is no __GFP_ZERO in the gfp
> flags khugepaged uses to allocate a huge page - in all common cases it
> would just be a waste of effort - so collapse_shmem() must remember to
> clear out any holes that it instantiates.
>
> The obvious place to do so, where they are put into the page cache tree,
> is not a good choice: because interrupts are disabled there. Leave it
> until further down, once success is assured, where the other pages are
> copied (before setting PageUptodate).
>
> Fixes: f3f0e1d2150b2 ("khugepaged: add support of collapse for tmpfs/shmem pages")
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 4.8+
Ouch. Thanks for catching this.
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
--
Kirill A. Shutemov
