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Mon, 13 Apr 2026 11:28:46 +0800 (CST) Received: from dggemv712-chm.china.huawei.com (unknown [10.1.198.32]) by mail.maildlp.com (Postfix) with ESMTPS id 3404940571; Mon, 13 Apr 2026 11:35:01 +0800 (CST) Received: from kwepemq500010.china.huawei.com (7.202.194.235) by dggemv712-chm.china.huawei.com (10.1.198.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 13 Apr 2026 11:35:01 +0800 Received: from [10.173.124.160] (10.173.124.160) by kwepemq500010.china.huawei.com (7.202.194.235) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 13 Apr 2026 11:35:00 +0800 Subject: Re: [PATCH v2 1/3] mm/memory-failure: report MF_MSG_KERNEL for reserved pages To: Breno Leitao CC: , , , , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan References: <20260331-ecc_panic-v2-0-9e40d0f64f7a@debian.org> <20260331-ecc_panic-v2-1-9e40d0f64f7a@debian.org> From: Miaohe Lin Message-ID: <1265c3f5-9fdc-8718-6323-147fcbf52de4@huawei.com> Date: Mon, 13 Apr 2026 11:34:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.124.160] X-ClientProxiedBy: kwepems100001.china.huawei.com (7.221.188.238) To kwepemq500010.china.huawei.com (7.202.194.235) X-Rspamd-Queue-Id: 3AFDD10000A X-Stat-Signature: 91wrx59gw15379byimpgg4zpcbmn3np9 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1776051304-18630 X-HE-Meta: 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 HJznri/Z ird7WmgciWgGg6KFp0d2fYjLlWmNYPVF9CS4fERYPgBQDk1HnKkqZSgCFrMgzqMj5hOnZ6NNYkTLZC8jw80hqCvYQ+UquEiBT4/mEhxxtpPX8LhDrMIRKCJvd2mIFr2h3/hmQg2HNoVyXl6ZogaOjciBxlcALaEjzTD8qSre0xaRUJBcAWlBtkpCyPHugBDGrxavoOoe6KebtA9CEeh0q1yUGY0rfpYzRI6g6DUhcfeJbygorxzzZsQdWOhuVyYpPvz9exh/xzUASVIFOgPSHd1DY6zWzSWl5LTOfneo0AL8crk9uZU2AbO0l48F16c1sgvnIdNmEuV8F51fcG2NnbIOJspmL6lvrmhNXeglfrA2YIWhTXfpdEmlFYVzJYIrJ1WVquX/7VJhL/5qAS836H8UppvaydkK63dHV Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026/4/10 22:03, Breno Leitao wrote: > On Tue, Apr 07, 2026 at 10:56:39AM +0800, Miaohe Lin wrote: >> On 2026/3/31 19:00, Breno Leitao wrote: >>> When get_hwpoison_page() returns a negative value, distinguish >>> reserved pages from other failure cases by reporting MF_MSG_KERNEL >>> instead of MF_MSG_GET_HWPOISON. Reserved pages belong to the kernel >>> and should be classified accordingly for proper handling by the >>> panic_on_unrecoverable_memory_failure mechanism. >>> >>> Signed-off-by: Breno Leitao >>> --- >>> mm/memory-failure.c | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >>> index ee42d4361309..6ff80e01b91a 100644 >>> --- a/mm/memory-failure.c >>> +++ b/mm/memory-failure.c >>> @@ -2432,7 +2432,11 @@ int memory_failure(unsigned long pfn, int flags) >>> } >>> goto unlock_mutex; >>> } else if (res < 0) { >>> - res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED); >>> + if (PageReserved(p)) >>> + res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); >> >> Is it safe or common to check page flags without holding extra refcnt? > > > Yes, this is safe. At this point the page has HWPoison set, preventing > reallocation. > > PageReserved is an atomic flag test on struct page memory that's always > valid for online PFNs. > > Reserved pages are inherently stable (kernel text, firmware, etc.) and > don't change status dynamically. > > This follows the same pattern as the existing is_free_buddy_page(p) > check a few lines above, which also reads page state without an extra > refcount. Got it. Thanks for your explanation. Thanks. .