From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (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 C9E8E3CCFAD; Mon, 13 Apr 2026 13:26:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=82.195.75.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776086820; cv=none; b=mU7WNt6foKpKTz34unjMR6RqBqWuSFHW5FM5vQqj4k32t3+xxopHNnNzGs4z/v6sNjabF+Z+jjsaMM/1MADA0GhLgxYQfcoL6PFcqJG4/jTFalO3+xHWfGeBFnc4T/tQtPZi1svFqioG8dM8Xgv6dSIXwr1rcVvMdKC6XgiwKzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776086820; c=relaxed/simple; bh=5kticVozScC6u8qmLk9+hhZd71yiocm3BKCHqXfpTvc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=B96+yO7rdXBmh8/azbxa4+fT7ieTbHq1EtPxTHCLXC48FxOgAGXu0UQbLX4BGHOMUZraTmB+p1yoPE7KM6EfiXoRGjUuTcEKX1IWqrIFaaEN35Bl3dWtCyYXUQjq9xfuPw5QN/eKL/CIqLbJhEoJ2Kaa/Syn++XTXzbEr1EVmWQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org; spf=none smtp.mailfrom=debian.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b=SegWXM+3; arc=none smtp.client-ip=82.195.75.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.b="SegWXM+3" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:Cc:To:In-Reply-To:References: Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description; bh=Ts5NH0xUvZdmVlkgq9z2yi5cSaxNAbH4JcbwnyOwfPI=; b=SegWXM+33+iQB4lzbciiQtJfqE y9zWi3WdYV5DpEeTro/sk84OUYQNQVXiNyWsbRLqt2/N/CcK9paVcPJMRqKbsthaKoz/3+sb9beNI 32BB5VuwvDNg5IYdhiB8D4GkP6b0PVIVf9kgcd6j2pdv3fhtNe2llJUC/6GN7RNCqkimqw2o/+OeO NKNCv7SIBZFbG4myyCZ+8dlwRID4SOHvnyI/s6P5IIpZ5dIjaQ6vtfYmLu3p/zCz8QvhgJkLoeZ26 KAkWfydAemXmFix9QXWrfWTCDPRnQZPYlEXq2vOUFVXsCPo8VrviOsUf/V66pCLP6SgF1rjhYamtx Gh5qEKDQ==; Received: from authenticated user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wCHJQ-00CKEQ-2C; Mon, 13 Apr 2026 13:26:48 +0000 From: Breno Leitao Date: Mon, 13 Apr 2026 06:26:33 -0700 Subject: [PATCH v3 1/3] mm/memory-failure: report MF_MSG_KERNEL for reserved pages Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260413-ecc_panic-v3-1-1dcbb2f12bc4@debian.org> References: <20260413-ecc_panic-v3-0-1dcbb2f12bc4@debian.org> In-Reply-To: <20260413-ecc_panic-v3-0-1dcbb2f12bc4@debian.org> To: Miaohe Lin , Naoya Horiguchi , Andrew Morton , Jonathan Corbet , Shuah Khan , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Breno Leitao , kernel-team@meta.com X-Mailer: b4 0.16-dev-453a6 X-Developer-Signature: v=1; a=openpgp-sha256; l=3839; i=leitao@debian.org; h=from:subject:message-id; bh=5kticVozScC6u8qmLk9+hhZd71yiocm3BKCHqXfpTvc=; b=owEBbQKS/ZANAwAIATWjk5/8eHdtAcsmYgBp3O8OGjMhJ00sPwi1tkdTGacpr0NdoWmXFCwqB fETGcica/uJAjMEAAEIAB0WIQSshTmm6PRnAspKQ5s1o5Of/Hh3bQUCadzvDgAKCRA1o5Of/Hh3 bTMOEACDVZS/51etxbpUL7Fkz6ajXdmMgOGgxmuNv7buSOZbViDuCi1ds2F/1rXwxwpxHG83XA3 KYdFSDzqS9bqK17+lFSC4W7hfOXqLUID2NYoVCuvKScI1sk6JL9UHn8Q8mQFh7ohtfQgnYRJd/p VSDvW4wpIgX8+UavBQCvtRr5QIaH2zAhJD6DD6OUBQyn8/l4LSFOfVZHtEiCkOJO2xB8HrHDtM1 UHQMlsndcKtDtErSj1OJlbqmy19xM/jD2HOf9zWN4RsGGOgz97uhbFYRHzb1ZgKdPagi+4Wm3v1 R4SYPz6OHHtb+orElndz4KXEwwozJA5N8Msh+7efgPPho7Jpxxl789+XZVNVEiXfpOzqMSRVZD3 DdnbIlV4hNrspnEz4iBuzVy9p5xJxn4yPSi4fmudxWGxon8iLyvzYdwGDhXi8kW5xzRvAh03Gry pttT2Vl7BcM81su4p1IOFRkj/WrBpcdWJOXhy4yzxkbHIEwYIHNldDBO5QRiRvm7zcGmY0R024/ 70ETzBG98+7b2FHdnFxlg7HzcOw9SRPCfF+ODwTOYVoEn0twZKFTT1GOqqLlvVKEcPVAlloxV/G OJfI0egBuyqFiBQIx8+pdyhjLqBKL/oY3hldDPmapM2IONXLZpO1kjwarMk4T8KCFQKbhTf58Sv ET1F4s/x9fIsJGg== X-Developer-Key: i=leitao@debian.org; a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao 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 by the panic_on_unrecoverable_memory_failure mechanism. Signed-off-by: Breno Leitao --- mm/memory-failure.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 48 insertions(+), 1 deletion(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ee42d43613097..852c595aff108 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -74,6 +74,8 @@ static int sysctl_memory_failure_recovery __read_mostly = 1; static int sysctl_enable_soft_offline __read_mostly = 1; +static int sysctl_panic_on_unrecoverable_mf __read_mostly; + atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); static bool hw_memory_failure __read_mostly = false; @@ -155,6 +157,15 @@ static const struct ctl_table memory_failure_table[] = { .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, + }, + { + .procname = "panic_on_unrecoverable_memory_failure", + .data = &sysctl_panic_on_unrecoverable_mf, + .maxlen = sizeof(sysctl_panic_on_unrecoverable_mf), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, } }; @@ -1281,6 +1292,35 @@ static void update_per_node_mf_stats(unsigned long pfn, ++mf_stats->total; } +/* + * Determine whether to panic on an unrecoverable memory failure. + * + * Design rationale: This design opts for immediate panic on kernel memory + * failures, capturing clean crashes other than random crashes on MF_IGNORED pages + * + * This panics on three categories of failures: + * - MF_MSG_KERNEL: Reserved pages that cannot be recovered + * - MF_MSG_KERNEL_HIGH_ORDER: High-order kernel pages that cannot be recovered + * - MF_MSG_UNKNOWN: Pages with unknown state that cannot be classified as recoverable + * - and the page is not being recovered (result = MF_IGNORED) + * + * Note: Transient races are mitigated by memory_failure()'s retry mechanism. + * When a buddy allocator race is detected (take_page_off_buddy() fails), the + * code clears PageHWPoison and retries the entire memory_failure() flow, + * allowing pages to be properly reclassified with updated flags. This ensures + * that false posiotives are not misclassified as unrecoverable. + * + */ +static bool panic_on_unrecoverable_mf(enum mf_action_page_type type, + enum mf_result result) +{ + return sysctl_panic_on_unrecoverable_mf && + result == MF_IGNORED && + (type == MF_MSG_KERNEL || + type == MF_MSG_KERNEL_HIGH_ORDER || + type == MF_MSG_UNKNOWN); +} + /* * "Dirty/Clean" indication is not 100% accurate due to the possibility of * setting PG_dirty outside page lock. See also comment above set_page_dirty(). @@ -1298,6 +1338,9 @@ static int action_result(unsigned long pfn, enum mf_action_page_type type, pr_err("%#lx: recovery action for %s: %s\n", pfn, action_page_types[type], action_name[result]); + if (panic_on_unrecoverable_mf(type, result)) + panic("Memory failure: %#lx: unrecoverable page", pfn); + return (result == MF_RECOVERED || result == MF_DELAYED) ? 0 : -EBUSY; } @@ -2432,7 +2475,11 @@ 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 (PageReserved(p)) + res = action_result(pfn, MF_MSG_KERNEL, MF_IGNORED); + else + res = action_result(pfn, MF_MSG_GET_HWPOISON, + MF_IGNORED); goto unlock_mutex; } -- 2.52.0