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t=1789138945; bh=1PTWyg4n3qpD4y/aa8UvIgM/ayJsqmzhh3ejIEE3QXI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=VZh6a5erCAhSab9ROCtz8BS6g7MI1jzhVXl1TxFBYM68Z+fltaZm1xEx6OLItP15Z nZmBVnNP1V+0/DmEZx6SzFV84s9DU1Cqc3gJdZgKEuLrXE8ZBhvx4UTF2zsQJmzQrU 1ESbS6pHuZFLaLsWPyN7kq3K9C94jNU3KLadDp0qGGPb0YqI8SxZOaAh8rd/J0rPK5 N7z3J3PXvkWkYOSJwSDPZrWHYbCcf4HyZ5juLbh027S7qlmCWyKCaa/zsagr+fkbEo rjY7sSzeoe/K7U4vNDmzPmvaXdunSPEXnnKxmE3D1cRrG2OGu0oUCAh5OqIXCJVYCC jemxJj67wfX/Q== Message-ID: <62160d6e-5409-4249-814b-cdc33b7d29df@kernel.org> Date: Fri, 11 Sep 2026 17:02:20 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] kselftest: mm: fix potential failure for merged VMA in guard-regions To: Yeoreum Yun , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com References: <20260911142904.1825452-1-yeoreum.yun@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 9D591A0013 X-Rspam-User: X-Stat-Signature: c7iaa58nox1mn3ipotsckhf3arwn5yje X-HE-Tag: 1789138946-199652 X-HE-Meta: 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 +jufscrz ccuZurECBPtlTVCTC0TCZFNNeabmClmqp9xt8HM4TX8EXCceqRbRc7Gm8FkEfCUHIWNhMAJI6Sab67ORG04Is9NfR5NuYU3FXzBr5hrDa8T3NjfZaHBGn5BzXftyb8EHaRjMNPp8wGO2O67HTDzGFtrMmie1cu4ZXUmhiLdKdjIB31y0fgOIdpy/gD3cNPCpGjKXTl96lzKn4HNpzxzJXB4k8kJFP8E823cOQ4xBRnxTXrPuuS3Nz/JGAv9hgTJuWmyvX5rT2mOT18NSkZyHjacF7OqNeC9DINi3mgQ1a+XW5SDytIlVvZRFaSI90/LRd+bX39B9s8R2xiBxYX3p6D9CxQvWfXByjPBLEtKPQF9LX//A= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/11/26 16:29, Yeoreum Yun wrote: > check_vmflag_guard() uses /proc/self/smaps to retrieve the VMA flags, > but this can fail if the mapping is merged with an adjacent VMA. > > To avoid this potential failure, first allocate a temporary region with > extra pages at both ends, unmap it, and then map the test region within > the temporary address range, leaving an unmapped page on each side to > prevent VMA merging. > > Signed-off-by: Yeoreum Yun > --- Acked-by: David Hildenbrand (Arm) -- Cheers, David