From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C80CF2D7DEA; Wed, 13 May 2026 20:10:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778703037; cv=none; b=Vt+al0QMMtKJSJ6bePb0wiiazhzFYFMX5p3pgLZRsnyOoTpHSuEIREeZwKY/RHwcrk6MUJtwcjPXVG2BOUQ0c8Bz0eYFcoyQ7BgU+Ff7Br2AHDGOLdZVUkLyQ/n3AfqiWvZIVrK2UHmB4pO3P1tt2sQGuf+K4evnKUwJX1IMzFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778703037; c=relaxed/simple; bh=Ev9k3KiPdRHS9B+BjW0upluVxxYhTSv2oMebgkf2ShA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZNrDDHzBNCQr/C+BhLE+l6+eLec7JjxB0lBqCzcTWwZARGhJIYy3IhWgf8mqurYFGILPxN6pczinFO27O8nLoAxkrClC0YR6tXBZ6AMxTYjfBoljHaH6JOCaIKhOqU7Gqpqpa59HwNrVqA01vsM+YmQx8f6y8HoidxquDs5Igdw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sGkHuXDR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sGkHuXDR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D228FC2BCB7; Wed, 13 May 2026 20:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778703037; bh=Ev9k3KiPdRHS9B+BjW0upluVxxYhTSv2oMebgkf2ShA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sGkHuXDRaCCU0nxxAGDBnblzSQhRReUx8USwaVA4cvDWXfAWRJpj0D8zQ7E51S0FJ e6g8K2kvYVF5vIGWc+rZN2qdyA/Rd+zRQwumJWggxdG7DyPFiF5hArQdO+2mn8/jEV sto0NYy8btd7x9JTg1K3aon0WvP431UqSg4CG8zlzefdF25D6wx0rYcyLvqBohNReD vwzEaWe2IITv4KV/YxDWpkPDlj9SLQLYFnNsw8Db3Evl7pmEWPVvwFlspehx4+84hJ olL/EQFbF3OPJdclgiGsF2k4/KRiFdBeNYL6cZ+Zz/fAgY+Q5d1eW6bgqP3ODAN0rY 7LULys9D6hHng== Message-ID: <5712adbc-b2fd-49fd-9827-cace47eff9ad@kernel.org> Date: Wed, 13 May 2026 22:10:27 +0200 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 1/6] mm/memory-failure: drop dead error_states[] entry for reserved pages To: Breno Leitao , Miaohe Lin , Andrew Morton , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , Naoya Horiguchi , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , "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 References: <20260513-ecc_panic-v7-0-be2e578e61da@debian.org> <20260513-ecc_panic-v7-1-be2e578e61da@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: <20260513-ecc_panic-v7-1-be2e578e61da@debian.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/13/26 17:39, Breno Leitao wrote: > The first entry of error_states[], > > { reserved, reserved, MF_MSG_KERNEL, me_kernel }, > > is unreachable. identify_page_state() has two callers, and neither > one can dispatch a PG_reserved page to me_kernel(): > > * memory_failure() reaches identify_page_state() only after > get_hwpoison_page() returned 1. get_any_page() reaches that > return only via __get_hwpoison_page(), which gates the refcount > on HWPoisonHandlable(). HWPoisonHandlable() rejects PG_reserved > pages, so they fail with -EBUSY/-EIO long before > identify_page_state() runs. You should clarify why they are rejected. There is no explicit check for PG_reserved in there! > > * try_memory_failure_hugetlb() reaches identify_page_state() on > the MF_HUGETLB_IN_USED branch, but the page is necessarily a > hugetlb folio there. The first table entry that matches a > hugetlb folio is { head, head, MF_MSG_HUGE, me_huge_page }, so > they dispatch to me_huge_page() before the (now-removed) > reserved entry would have matched, regardless of whether > PG_reserved happens to be set on the head page. See hugetlb_folio_init_vmemmap(): we always clear PG_reserved for hugetlb folios allocated from memblock. > > me_kernel() never executes and the entry exists only to be matched > against by code that cannot see it. > > Drop the entry, the me_kernel() helper, and the now-unused > "reserved" macro. Leave the MF_MSG_KERNEL enum value in place: it > remains part of the tracepoint and pr_err() string tables, and > follow-on work to classify unrecoverable kernel pages can reuse it > without churning the user-visible enum. > > No functional change. > > Suggested-by: David Hildenbrand > Signed-off-by: Breno Leitao > --- > mm/memory-failure.c | 14 -------------- > 1 file changed, 14 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 866c4428ac7ef..49bcfbd04d213 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -992,17 +992,6 @@ static bool has_extra_refcount(struct page_state *ps, struct page *p, > return false; > } > > -/* > - * Error hit kernel page. > - * Do nothing, try to be lucky and not touch this instead. For a few cases we > - * could be more sophisticated. > - */ > -static int me_kernel(struct page_state *ps, struct page *p) > -{ > - unlock_page(p); > - return MF_IGNORED; > -} > - > /* > * Page in unknown state. Do nothing. > * This is a catch-all in case we fail to make sense of the page state. > @@ -1211,10 +1200,8 @@ static int me_huge_page(struct page_state *ps, struct page *p) > #define mlock (1UL << PG_mlocked) > #define lru (1UL << PG_lru) > #define head (1UL << PG_head) > -#define reserved (1UL << PG_reserved) > > static struct page_state error_states[] = { > - { reserved, reserved, MF_MSG_KERNEL, me_kernel }, > /* > * free pages are specially detected outside this table: > * PG_buddy pages only make a small fraction of all free pages. > @@ -1246,7 +1233,6 @@ static struct page_state error_states[] = { > #undef mlock > #undef lru > #undef head > -#undef reserved > > static void update_per_node_mf_stats(unsigned long pfn, > enum mf_result result) > Yes, I think this should work. Acked-by: David Hildenbrand (Arm) -- Cheers, David