Re: [PATCH 2/9] mm: khugepaged: fix radix tree node leak in shmem collapse error path

From: Kirill A. Shutemov
Date: Thu Nov 17 2016 - 18:21:43 EST

On Thu, Nov 17, 2016 at 02:11:31PM -0500, Johannes Weiner wrote:
> The radix tree counts valid entries in each tree node. Entries stored
> in the tree cannot be removed by simpling storing NULL in the slot or
> the internal counters will be off and the node never gets freed again.
> When collapsing a shmem page fails, restore the holes that were filled
> with radix_tree_insert() with a proper radix tree deletion.
> Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
> Reported-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

Kirill A. Shutemov