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 B221E25B092; Wed, 13 May 2026 11:48:19 +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=1778672899; cv=none; b=B4vX0oObjKRLCIfJTDVdanzeSLVLKhOFC223+J7JED9koRh2O38FUQvnFbFvxWVR8TPvzlz1AEl/yE74k++UNX+GtdSwqg4sytsjReI26GruBNLPdC2mZGH3itvq+03iuPllxxFE3WGf/EBuGiE5srJ4hVidBPWzMG92xrmpZR4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778672899; c=relaxed/simple; bh=6SsqoKOotrL8ImGaZxMJB/vHRv7t8SzBAUCminkkLtQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CQ5YF9UlcTUaXqMPOZPcojNset2eiHpcML1xuiPf+5DnCl92r6KsrUU9Al9pLnrooOb5k0YnqxvkGngPtt1uxz5tJdXYydl5zlklfZRK2wtCuBDL6EA7jULVcYASXbz8uWv51A+amwc7soCqTbO9CaZH3hVSlfOwLSMNxkR+AhY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fe+ZJqt8; 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="fe+ZJqt8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB1BCC2BCB7; Wed, 13 May 2026 11:48:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778672899; bh=6SsqoKOotrL8ImGaZxMJB/vHRv7t8SzBAUCminkkLtQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=fe+ZJqt84+2lMlaa6rou22hlRZGeWIU61oh+Y19FSZLBWom/w/0qOdxOPqfcxmH4i WiOT/lHJQs+yVtlW34v0D5Y00mXnAySDtmwuDGQQn6NM+IAiHEA0fd8vqo/idin85w 9m4h1y42Qp806JY3vLaNJ2/KKnIoEO/ldPjggl5Xekubs8OD/xzdWwUptQS46qyQ+G tu62E6sa5hRB6iUkuNB3I2/FQh9bNep88xf0DSbbTjb8oVz6oz1TBIL2540A+gvhw2 BsE4yzcO/NGPntfo07dZAqW954WLuNnGz8Sq2L7MjaB0Ghq7T0uVpkde3wx3wvu8Pp +4nYivhm8TqQQ== Message-ID: <3e5e8fb8-6957-46b7-9777-0ed1bff1d0fb@kernel.org> Date: Wed, 13 May 2026 13:48:11 +0200 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 2/4] mm/memory-failure: classify get_any_page() failures by reason To: Breno Leitao Cc: 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" , 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-v6-2-183012ba7d4b@debian.org> <28b01c14-3d87-4cab-b695-5b9015578785@kernel.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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/12/26 15:33, Breno Leitao wrote: > On Tue, May 12, 2026 at 10:21:50AM +0200, David Hildenbrand (Arm) wrote: >> >>> } >>> goto unlock_mutex; >>> } else if (res < 0) { >>> - if (is_reserved) >>> + /* >>> + * Promote a stable unhandlable kernel page diagnosed by >>> + * get_hwpoison_page() to MF_MSG_KERNEL alongside reserved >>> + * pages; transient lifecycle races stay as MF_MSG_GET_HWPOISON. >>> + */ >>> + if (is_reserved || gp_status == MF_GET_PAGE_UNHANDLABLE) >>> res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); >> >> >> It's all a bit of a mess. get_hwpoison_page() should just indicate that a page >> is unhandable if it is PG_reserved? > > Are you saying that we should identify if the page is PG_reserved in > get_hwpoison_page() instead of in memory_failure(), as done in the > previous patch ("mm/memory-failure: report MF_MSG_KERNEL for reserved > pages") ? > >> Why can't we just return a special error code from get_hwpoison_page()? We ahve >> plenty of errno values to chose from. > > Something like: > > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 866c4428ac7ef..0a6d83575833e 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -878,7 +878,7 @@ static const char *action_name[] = { > }; > > static const char * const action_page_types[] = { > - [MF_MSG_KERNEL] = "reserved kernel page", > + [MF_MSG_KERNEL] = "unrecoverable kernel page", > [MF_MSG_KERNEL_HIGH_ORDER] = "high-order kernel page", > [MF_MSG_HUGE] = "huge page", > [MF_MSG_FREE_HUGE] = "free huge page", > @@ -1394,6 +1394,21 @@ static int get_any_page(struct page *p, unsigned long flags) > int ret = 0, pass = 0; > bool count_increased = false; > > + if (PageReserved(p)) { > + ret = -ENOTRECOVERABLE; > + goto out; > + } > + > if (flags & MF_COUNT_INCREASED) > count_increased = true; > > @@ -1422,7 +1437,7 @@ static int get_any_page(struct page *p, unsigned long flags) > shake_page(p); > goto try_again; > } > - ret = -EIO; > + ret = -ENOTRECOVERABLE; > goto out; > } > } > @@ -1441,10 +1456,10 @@ static int get_any_page(struct page *p, unsigned long flags) > goto try_again; > } > put_page(p); > - ret = -EIO; > + ret = -ENOTRECOVERABLE; > } > out: > - if (ret == -EIO) > + if (ret == -EIO || ret == -ENOTRECOVERABLE) > pr_err("%#lx: unhandlable page.\n", page_to_pfn(p)); > > return ret; > @@ -2431,6 +2448,9 @@ int memory_failure(unsigned long pfn, int flags) > res = action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED); > } > goto unlock_mutex; > + } else if (res == -ENOTRECOVERABLE) { > + res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); > + goto unlock_mutex; > } else if (res < 0) { > res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED); > goto unlock_mutex; That might probably read nicer as switch (res) { case 0: ... case 1: ... case -ENOTRECOVERABLE: ... case ... default: } > > > If that is what you are suggestion, maybe we can create another > MF_MSG_RESERVED? and another return value for get_any_page() to track > the reserve pages ? I guess "reserved" is really just like most other kernel pages. So I wouldn't special-case them here. Or would there be a good reason? -- Cheers, David