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Date:   Wed, 19 Apr 2023 12:49:02 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Peng Zhang <zhangpeng.00@bytedance.com>
Cc:     Liam.Howlett@oracle.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org
Subject: Re: [PATCH] maple_tree: Fix allocation in mas_sparse_area()
Message-Id: <20230419124902.7cb9b5c54afa37736e7b0e3a@linux-foundation.org>
In-Reply-To: <20230419093625.99201-1-zhangpeng.00@bytedance.com>
References: <20230419093625.99201-1-zhangpeng.00@bytedance.com>
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On Wed, 19 Apr 2023 17:36:25 +0800 Peng Zhang <zhangpeng.00@bytedance.com> wrote:

> In the case of reverse allocation, mas->index and mas->last do not point
> to the correct allocation range, which will cause users to get incorrect
> allocation results, so fix it. If the user does not use it in a specific
> way, this bug will not be triggered.

Please describe the user-visible effects of the bug.  I assume "none",
because there are presently no callers which can trigger it?

> Also re-checks whether the size is still satisfied after the lower bound
> was increased, which is a corner case and is incorrect in previous versions.

Again, what are the user-visible effects of the bug?