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Date:   Fri, 28 Sep 2018 07:35:48 -0400
From:   Josef Bacik <josef@toxicpanda.com>
To:     Kirill Tkhai <ktkhai@virtuozzo.com>
Cc:     akpm@linux-foundation.org, gorcunov@openvz.org, mhocko@suse.com,
        aryabinin@virtuozzo.com, hannes@cmpxchg.org,
        penguin-kernel@I-love.SAKURA.ne.jp, shakeelb@google.com,
        jbacik@fb.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: Fix int overflow in callers of do_shrink_slab()
Message-ID: <20180928113546.sc7cztwsja4advli@destiny>
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On Fri, Sep 28, 2018 at 02:28:32PM +0300, Kirill Tkhai wrote:
> do_shrink_slab() returns unsigned long value, and
> the placing into int variable cuts high bytes off.
> Then we compare ret and 0xfffffffe (since SHRINK_EMPTY
> is converted to ret type).
> 
> Thus, big number of objects returned by do_shrink_slab()
> may be interpreted as SHRINK_EMPTY, if low bytes of
> their value are equal to 0xfffffffe. Fix that
> by declaration ret as unsigned long in these functions.
> 
> Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef