From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4917934389D for ; Tue, 30 Jun 2026 20:55:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782852937; cv=none; b=VEfE46fGVWAkXrj0umWwl5HzJbGLvBmyQ/UNSzJ0FBnn6P4spgMhkOOoPBXvQ0eF+lMFDd7+OchDqbXALyt95tmHOWq8OYvYXSNj//aYxFk/iEiUUPzHAU6YcGee8Ob014rF3bEXl/Nc04NARN4f7FAOPK+ERkOPebPrzdrcMEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782852937; c=relaxed/simple; bh=syZ5P45PHOLqeP0MaWV/QQ2fNBV77sqX3p4ylmC2iSk=; h=Date:To:From:Subject:Message-Id; b=hC5ujJjAXJY34xYDRJHYAaaaltdbv2ClN4hmFzwivCOAXM9Z1veCso8QrnUkt5DdCvXKkFjieW6wgJFEyA4coV3Tl5WrSZVJCnXjri2TR+Xw+PJkshee87fQIq2gTfF9YgktLNajsHomIx3ayTXEFZT34xL0JRlSoDpbU7cnEJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=puzzkgSK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="puzzkgSK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC9851F000E9; Tue, 30 Jun 2026 20:55:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1782852936; bh=KHdPQiqjxnjBfJYVHnPZ9UGBlugzl5bg5IQHxyJBJeg=; h=Date:To:From:Subject; b=puzzkgSKqzeZ1lm1tkFhh0yZAjtoYdM2fdwFvCZXRNTc7B7vEVhsT3UOX+ovTWoJd SfLgBK4GiUZ415rI1PbNf3W5AyiPN/SaaGcTaD0B1W5rMlNlx96QqTeAe+6UnzET15 dPsRreyDtuiYLgxz3cOgXDx7pTM8W5iVCHQa+9v8= Date: Tue, 30 Jun 2026 13:55:35 -0700 To: mm-commits@vger.kernel.org,leitao@debian.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-memory-failure-drop-dead-error_states-entry-for-reserved-pages.patch added to mm-unstable branch Message-Id: <20260630205535.DC9851F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/memory-failure: drop dead error_states[] entry for reserved pages has been added to the -mm mm-unstable branch. Its filename is mm-memory-failure-drop-dead-error_states-entry-for-reserved-pages.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-failure-drop-dead-error_states-entry-for-reserved-pages.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Breno Leitao Subject: mm/memory-failure: drop dead error_states[] entry for reserved pages Date: Tue, 30 Jun 2026 05:46:04 -0700 Patch series "mm/memory-failure: add panic option for unrecoverable pages", v10. A multi-bit ECC error on a kernel-owned page that the memory failure handler cannot recover is currently swallowed: PG_hwpoison is set, the event is logged, and the kernel keeps running. The corrupted memory remains accessible to the kernel and either drives silent data corruption or surfaces seconds-to-minutes later as an apparently unrelated crash. In a large fleet that delayed, unattributable crash turns into significant engineering effort to root-cause; in a kdump configuration, by the time the crash happens the original error context (faulting PFN, MCE/GHES record, page state) is long gone. This series adds an opt-in sysctl, vm.panic_on_unrecoverable_memory_failure, that converts an unrecoverable kernel-page hwpoison event into an immediate panic with a clean dmesg/vmcore that still contains the original failure context. The default is disabled so existing workloads see no change. There is a selftest that test different cases, and I tested it using the following variants: ┌─────────┬──────────┬───────────────────────────────────────────────────────────┐ │ Variant │ PFN │ Result │ ├─────────┼──────────┼───────────────────────────────────────────────────────────┤ │ rodata │ 0x2600 │ Panic with "Memory failure: 0x2600: unrecoverable page" │ ├─────────┼──────────┼───────────────────────────────────────────────────────────┤ │ slab │ 0x100032 │ Panic with "Memory failure: 0x100032: unrecoverable page" │ ├─────────┼──────────┼───────────────────────────────────────────────────────────┤ │ pgtable │ 0x100000 │ Panic with "Memory failure: 0x100000: unrecoverable page" │ └─────────┴──────────┴───────────────────────────────────────────────────────────┘ Each one shows the same call trace, exactly the path the series builds: hard_offline_page_store → memory_failure → action_result → panic("Memory failure: %#lx: unrecoverable page") This patch (of 6): 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 only takes a refcount when the page is HWPoisonHandlable(). HWPoisonHandlable() is an allowlist for LRU, free-buddy, and (for soft-offline) movable_ops pages -- PG_reserved pages do not satisfy any of these, so they fail with -EBUSY/-EIO long before identify_page_state() runs. * try_memory_failure_hugetlb() reaches identify_page_state() only via the MF_HUGETLB_IN_USED branch, where the page is necessarily a hugetlb folio. hugetlb folios don't carry PG_reserved at that point: hugetlb_folio_init_vmemmap() calls __folio_clear_reserved() during init, so the reserved entry would not match even if it were still present. 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. Link: https://lore.kernel.org/20260630-ecc_panic-v10-0-c6ed5b62eea2@debian.org Link: https://lore.kernel.org/20260630-ecc_panic-v10-1-c6ed5b62eea2@debian.org Signed-off-by: Breno Leitao Suggested-by: David Hildenbrand Acked-by: David Hildenbrand (Arm) Reviewed-by: Lance Yang Acked-by: Miaohe Lin Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: "Masami Hiramatsu (Google)" Cc: Mathieu Desnoyers Cc: Michal Hocko Cc: Mike Rapoport Cc: Naoya Horiguchi Cc: Shuah Khan Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/memory-failure.c | 14 -------------- 1 file changed, 14 deletions(-) --- a/mm/memory-failure.c~mm-memory-failure-drop-dead-error_states-entry-for-reserved-pages +++ a/mm/memory-failure.c @@ -981,17 +981,6 @@ static bool has_extra_refcount(struct pa } /* - * 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. */ @@ -1199,10 +1188,8 @@ static int me_huge_page(struct page_stat #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. @@ -1234,7 +1221,6 @@ 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) _ Patches currently in -mm which might be from leitao@debian.org are mm-kmemleak-avoid-soft-lockup-when-scanning-task-stacks.patch mm-kmemleak-stop-the-task-stack-scan-early-when-interrupted.patch mm-kmemleak-stop-the-per-cpu-and-struct-page-scans-early-too.patch mm-memory-failure-drop-dead-error_states-entry-for-reserved-pages.patch mm-memory-failure-surface-unhandlable-kernel-pages-as-enotrecoverable.patch mm-memory-failure-report-mf_msg_kernel-for-unrecoverable-kernel-pages.patch mm-memory-failure-add-panic-option-for-unrecoverable-pages.patch documentation-document-panic_on_unrecoverable_memory_failure-sysctl.patch selftests-mm-add-hwpoison-panic-destructive-test.patch mm-kmemleak-skip-the-remaining-scan-phases-when-interrupted.patch