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Date:   Sun, 10 Sep 2023 14:26:27 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Xiu Jianfeng <xiujianfeng@huaweicloud.com>
Cc:     Liam.Howlett@oracle.com, willy@infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, xiujianfeng@huawei.com
Subject: Re: [PATCH] mm: remove duplicated vma->vm_flags check when
 expanding stack
Message-Id: <20230910142627.0dce42578bfaab7c4c67e316@linux-foundation.org>
In-Reply-To: <20230906103312.645712-1-xiujianfeng@huaweicloud.com>
References: <20230906103312.645712-1-xiujianfeng@huaweicloud.com>
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On Wed,  6 Sep 2023 10:33:12 +0000 Xiu Jianfeng <xiujianfeng@huaweicloud.com> wrote:

> expand_upwards() and expand_downwards() will return -EFAULT if VM_GROWSUP
> or VM_GROWSDOWN is not correctly set in vma->vm_flags, however in
> !CONFIG_STACK_GROWSUP case, expand_stack_locked() returns -EINVAL first
> if !(vma->vm_flags & VM_GROWSDOWN) before calling expand_downwards(), to
> keep the consistency with CONFIG_STACK_GROWSUP case, remove this check.

What are the user-visible effects of this change?

Do you believe this fix should be backported into earlier kernel versions?