From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793699341; b=ecvFUg1QQ4N5CDLeqa1F/kC2tK0JrFfLJdnyYNQO62TQ+yuQfPOeZ/p1Z/gReir5zaXn uyXu1hWXl/sKyo2FEJe2TbRiO5ZBVqA/UjQW6bq0R/KVB1HO+RLyJEBw4M3cdfxcFxdrc 4vpzwxRnDXIh7JcNjSFXyixMC5vERrsCUfVtlaXNW7HYiGMbUBpUBBETEJfjjOHZPtvUs I/KMWVuqef0YeeeDUElpV3gk/kqkprB/wzNFuuLTnvUjSsdI6OdwDgmI2yAqWZJ+o08jg 8boPCUsDnsb5xURQe5k++0tqQeMCAiMBaxJHiWtFdkZqU4QHHPxz4iTcmCDGA10oUKQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793699341; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=cgwH7+eb4DO1f1hZBo5/HU3TXgqaVoeCZLybivmvUJo=; b=uvb4NzaOh/gx1RbbQeyIChyd5i1jL4GqNXp/K9f+yzRY/Sz3MKzZKrA9gzt9o+mshRYp ouAt/C1nkR/B0EDJuhsmo9lg2M5qfykNyGQtDh1dSMCYkkjh19VOVElZ/0tYDKb0hALoM DhxV6v9NruVmNTRY/kawW4An01BLsC2gC9j8iJB+T/BD07o7/u4olQyOBhCCckNYgntGf s8l1mMPcZzc80u1t6DtOmc0YzKI4Wm4kpDPpv21PVqDMcr6a1EJwYE/BBVvy9P/J58AdR vYvrA+5jDhKpPHEpNebFHHhMlps1hzzsPqYC56+chpChldwrQP6k/f35wuMlZnylgyQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GV++1Djw; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 049AE606A327; Tue, 3 Nov 2026 09:49:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GV++1Djw Received: by smtp.kernel.org (Postfix) with ESMTPSA id A74261F000C1; Tue, 3 Nov 2026 09:48:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793699340; bh=cgwH7+eb4DO1f1hZBo5/HU3TXgqaVoeCZLybivmvUJo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=GV++1DjwxRqBZTgtqKQjH8FDRWWNjQ0UExyz4D4wPRG6CXHgHqlai8IgSZ5/B9AVO fyr6sYpt+ugUguBnTwfa9EONvXK3lfiCOo8fFL2gesEHkb4WUZGfvT6fCfMJNsI31Z Vw/EI3JAg4jrRuPcmYktzzSqUrEL7bUe5ETL5f1c0mbZHI+qxZizlD4FmPKJbOX8x8 UcFo7Cvy49IASUxO9wd2cXytT8/WMCHJsvvJP/mjOG1ZnH5zkongCwU5jFXzRP2W/i UHtO33zaLptW2P5/6tQLOOQzYQ1+oU9XS++2xZHKEc1aCasgMoti+lnda5b6BltK8l casrwkwEvaa2g== Date: Tue, 3 Nov 2026 11:48:43 +0200 From: Mike Rapoport To: Breno Leitao Cc: Ard Biesheuvel , Ilias Apalodimas , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Miaohe Lin , Naoya Horiguchi , Oscar Salvador , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Catalin Marinas , Will Deacon , Mark Rutland , kas@kernel.org, kexec@lists.infradead.org, Brendan Jackman , Johannes Weiner , Zi Yan , shakeel.butt@linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-arm-kernel@lists.infradead.org, rmikey@meta.com, riel@surriel.com, harry@kernel.org, kernel-team@meta.com Subject: Re: [PATCH v6 3/7] mm/memory-failure: add hwpoison_boot_page() to flag an inherited frame Message-ID: References: <20261016-hwpoison-kho-v6-0-f304255147da@debian.org> <20261016-hwpoison-kho-v6-3-f304255147da@debian.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261016-hwpoison-kho-v6-3-f304255147da@debian.org> On Fri, Oct 16, 2026 at 05:15:43AM -0700, Breno Leitao wrote: > A kernel that kexecs inherits the frames its predecessor found > hardware-poisoned. It has to carry them as PG_hwpoison in its own memmap, > so that everything that already understands the flag covers them, > including the kexec segment placement check. > > Add a helper that sets the flag and counts the frame in > num_poisoned_pages. It runs while the memmap is initialised, before > memory_dev_init() has run. memblk_nr_poison_inc() divides by > sections_per_block, which memory_dev_init() sets, so the helper > increments num_poisoned_pages itself instead of calling > num_poisoned_pages_inc(). > > An inherited frame is a hardware failure like any other, so the helper > sets hw_memory_failure. Without it, unpoison_memory() accepts the frame, > clears the flag and drops the last reference, which frees a frame that > is still bad. > > The helper also counts the frame as managed, as a frame that fails at > run time stays counted. Memory offlining subtracts every frame of the > block that is not PageOffline, so a frame that was never counted leaves > the managed page count too low after an offline. > > The per-node memory failure statistics are not updated. This kernel > handled no failure, it only inherited one. > > Signed-off-by: Breno Leitao > --- > mm/internal.h | 5 +++++ > mm/memory-failure.c | 8 ++++++++ > 2 files changed, 13 insertions(+) > > diff --git a/mm/internal.h b/mm/internal.h > index da14c56fb24e11..4bd3bbce86e0ad 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -1169,6 +1169,7 @@ void SetPageHWPoisonTakenOff(struct page *page); > void ClearPageHWPoisonTakenOff(struct page *page); > bool take_page_off_buddy(struct page *page); > bool put_page_back_buddy(struct page *page); > +void __init hwpoison_boot_page(struct page *page); > struct task_struct *task_early_kill(struct task_struct *tsk, int force_early); > void add_to_kill_ksm(struct task_struct *tsk, const struct page *p, > struct vm_area_struct *vma, struct list_head *to_kill, > @@ -1181,6 +1182,10 @@ static inline int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, b > { > return -EBUSY; > } > + > +static inline void hwpoison_boot_page(struct page *page) > +{ > +} > #endif We've been splitting internal.h to smaller headers, maybe it's time to add "memory-faulure.h"? > extern unsigned long __must_check vm_mmap_pgoff(struct file *, unsigned long, > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index a2ca8df501caee..d0d6b184ee469f 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -96,6 +96,14 @@ void num_poisoned_pages_sub(unsigned long pfn, long i) > memblk_nr_poison_sub(pfn, i); > } > > +void __init hwpoison_boot_page(struct page *page) > +{ > + SetPageHWPoison(page); > + atomic_long_inc(&num_poisoned_pages); > + hw_memory_failure = true; > + adjust_managed_page_count(page, 1); > +} > + > /* > * Return the first or the last hardware-poisoned online page in [start, > * start + size), or PHYS_ADDR_MAX if the range is clean. > > -- > 2.53.0-Meta > -- Sincerely yours, Mike.