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

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Message-ID: <20161117232134.GB8358@node>
Date:   Fri, 18 Nov 2016 02:21:34 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Johannes Weiner <hannes@...xchg.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, Jan Kara <jack@...e.cz>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH 2/9] mm: khugepaged: fix radix tree node leak in shmem
 collapse error path

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@...e.cz>
> Signed-off-by: Johannes Weiner <hannes@...xchg.org>

Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>

-- 
 Kirill A. Shutemov