From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 85054CD4855 for ; Tue, 12 May 2026 08:17:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC0106B0092; Tue, 12 May 2026 04:17:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E70F36B0093; Tue, 12 May 2026 04:17:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D87226B0095; Tue, 12 May 2026 04:17:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id C94386B0092 for ; Tue, 12 May 2026 04:17:08 -0400 (EDT) Received: from smtpin22.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 7871E1C02CE for ; Tue, 12 May 2026 08:17:08 +0000 (UTC) X-FDA: 84758062536.22.80CA118 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf03.hostedemail.com (Postfix) with ESMTP id 7DBBE20005 for ; Tue, 12 May 2026 08:17:06 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=s96bi0US; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778573826; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=bZkIynSNQ91xYPmfx9b5g8BPtFpBwQHdsgoNWQ7WJUI=; b=xubJHZL6IHZeutXdicipk5RkzvQ1G4yIWpBoz0hcVsHEz0xT1b4G4J/mc0wIpZZ25UhCpE 1KUqWy36Nvfbt0UskZLIKoX59oLcMH9+CyYVKPZuw92d4G6kOjVdKmTRa/Ekn1slt4ncPu +dYaybcsk1L+QR+SpZKtguwJJPTI4wU= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778573826; a=rsa-sha256; cv=none; b=xLXQpNw2GG+91GEEbwlQoYvD6rS1MxYQ013i4MO8dds4UKRwsG0T071/uB5+pL3R6W+9BV FLF14PxfJxfGxYoucWeO3ekC7wg5gzj3OEbvfXcEZX6RdWqHZLG8BKUpvzEXuS2waB8Kim gz4WhJB6V52vzc9+KGRxeZtq0MNGfTE= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=s96bi0US; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id D849D600CB; Tue, 12 May 2026 08:17:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78B3FC2BCB0; Tue, 12 May 2026 08:17:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778573825; bh=tLCdh/n3r829zo7nnZ+f729oceajn5PFZJ92fEGwgYg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=s96bi0USUPujrkqhfCW0mIF3GtkQT8zV//g9jBbpXw0g1s7ZbvpTI4vdqJ9EDKwLx h1s0vweRTLdVDZiNA24tDeB0THJxbOti0u6c8bf77fONzt/qJKcYFbXaX5FArU423K 9AnbfFL384pg317tkfvrKVfEvFUzfQkmXRcyHBvtXdRzG2TkzFFyn0s8w/ir4A75Hm pYjauvJpL/KWlqQLVDVoZ9dgT0iuqyEtvZx9XjOpvmxS+1bBoDzhTscxhFx360z7Za pJbK1NuXGFTEymLyjgMExHjMFiAElrS3ZBcCvVk6YoRwVRduUzgJjYEGl8Bvlu2OWO RSoZHgVvNg9/A== Message-ID: <9504c193-8c01-4d03-8f62-c50fd7fbdbc0@kernel.org> Date: Tue, 12 May 2026 10:17:00 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 1/4] mm/memory-failure: report MF_MSG_KERNEL for reserved pages To: Breno Leitao , Miaohe Lin , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , "Liam R. Howlett" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kernel-team@meta.com, Lance Yang References: <20260511-ecc_panic-v6-0-183012ba7d4b@debian.org> <20260511-ecc_panic-v6-1-183012ba7d4b@debian.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260511-ecc_panic-v6-1-183012ba7d4b@debian.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 7DBBE20005 X-Rspam-User: X-Stat-Signature: xh7uhebk1c5thecmdnt7c5nb9x7kkd5i X-HE-Tag: 1778573826-825618 X-HE-Meta: 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 UdnzYpLc uwWwh0nvQvpUBCyIchvF7sXmktMtwa5dg9KTGtJheyPKizaakzt6+ACGwxbUVtcHjlZlrDSuExCd29WWAzW9gFHxAkCaExi3k//oA/5FDUGgTbHfHLMCHNwTqzh7O9eb3S829y1dF8+YEoRaYEvn4rl7B6o/B+f7TaGffuRZQ5aupRLiPoDWJ7SFmr5NxM7UD8mZAshGKkw4JwZM0mcu52zwdFd3qyvU0mZUpGESVEZV+LeSx8bhq/T63rDY5+rwJKYJ+xLY8wJKvx1tldPQwcCbvspmZ16rNmQ16FswV4czDUq7aweZqCsOT9N0zMZqaocol1WyiyCy9B2Lf92XkfCaJeofPtNvbY+60/W9p5x4YqLloYUwQVuxZc0xxNZDXlN7zwkjtYPDW/AjXR6ir3Dd5YPS8QXyeNnlHGI8rCAnTURzD2VM+ZRYFadfw+Hl6QDrItVU3mNUFg7wze0jSyuZwuA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/11/26 17:38, 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. > > Sample PG_reserved before the get_hwpoison_page() call. In the > MF_COUNT_INCREASED path get_any_page() can drop the caller's > reference before returning -EIO, after which the underlying page may > have been freed and reallocated with page->flags reset; reading > PageReserved(p) at that point would observe stale or unrelated state. > The pre-call snapshot reflects what the page actually was at the > time of the failure event. > > Acked-by: Miaohe Lin > Reviewed-by: Lance Yang > Signed-off-by: Breno Leitao > --- > mm/memory-failure.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 866c4428ac7ef..f112fb27a8ff6 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -2348,6 +2348,7 @@ int memory_failure(unsigned long pfn, int flags) > unsigned long page_flags; > bool retry = true; > int hugetlb = 0; > + bool is_reserved; > > if (!sysctl_memory_failure_recovery) > panic("Memory failure on page %lx", pfn); > @@ -2411,6 +2412,18 @@ int memory_failure(unsigned long pfn, int flags) > * In fact it's dangerous to directly bump up page count from 0, > * that may make page_ref_freeze()/page_ref_unfreeze() mismatch. > */ > + /* > + * Pages with PG_reserved set are not currently managed by the > + * page allocator (memblock-reserved memory, driver reservations, > + * etc.), so classify them as kernel-owned for reporting. > + * > + * Sample the flag before get_hwpoison_page(): in the > + * MF_COUNT_INCREASED path, get_any_page() can drop the caller's > + * reference before returning -EIO, after which page->flags may > + * have been reset by the allocator. > + */ > + is_reserved = PageReserved(p); > + > res = get_hwpoison_page(p, flags); > if (!res) { > if (is_free_buddy_page(p)) { > @@ -2432,7 +2445,11 @@ 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 (is_reserved) > + res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); > + else > + res = action_result(pfn, MF_MSG_GET_HWPOISON, > + MF_IGNORED); > goto unlock_mutex; > } > > It's a bit odd that we need this handling when we already have handling for reserved pages in error_states[]. HWPoisonHandlable() would always essentially reject PG_reserved pages. So __get_hwpoison_page() ... would always fail? Making get_hwpoison_page()->get_any_page() always fail? But then, we never call identify_page_state()? And never call me_kernel()? This all looks very odd. Why would you even want to call get_hwpoison_page() in the first place if you find PageReserved? -- Cheers, David