From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AE50C433FE for ; Mon, 13 Sep 2021 14:25:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 160AF60F26 for ; Mon, 13 Sep 2021 14:25:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344121AbhIMO0f (ORCPT ); Mon, 13 Sep 2021 10:26:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:42328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346315AbhIMOYW (ORCPT ); Mon, 13 Sep 2021 10:24:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4F4EF61B3E; Mon, 13 Sep 2021 13:48:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631540884; bh=URB8kG7j7JXbGwk4FRLk6yfl4EOoaAnhuT74pNPHgGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hb7QHehT6GOf44fWBN31rTQKhbYriSmdefXSzJyX5PmyELMAI2Xb63ZsTxuqpMxLj 2YCsLKc3FRq+IyhJP1QFQKd8sAvDu1tA5RdguKzs0I9oH1IBAT4tFCiBsbPqLPgHvx TiZxg2OrIl44CwwSHdNHuPVn1tPGi8zSBtasJXEA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sumanth Kamatala , Borislav Petkov , Tony Luck , Sasha Levin Subject: [PATCH 5.14 075/334] x86/mce: Defer processing of early errors Date: Mon, 13 Sep 2021 15:12:09 +0200 Message-Id: <20210913131115.934577590@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210913131113.390368911@linuxfoundation.org> References: <20210913131113.390368911@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Borislav Petkov [ Upstream commit 3bff147b187d5dfccfca1ee231b0761a89f1eff5 ] When a fatal machine check results in a system reset, Linux does not clear the error(s) from machine check bank(s) - hardware preserves the machine check banks across a warm reset. During initialization of the kernel after the reboot, Linux reads, logs, and clears all machine check banks. But there is a problem. In: 5de97c9f6d85 ("x86/mce: Factor out and deprecate the /dev/mcelog driver") the call to mce_register_decode_chain() moved later in the boot sequence. This means that /dev/mcelog doesn't see those early error logs. This was partially fixed by: cd9c57cad3fe ("x86/MCE: Dump MCE to dmesg if no consumers") which made sure that the logs were not lost completely by printing to the console. But parsing console logs is error prone. Users of /dev/mcelog should expect to find any early errors logged to standard places. Add a new flag MCP_QUEUE_LOG to machine_check_poll() to be used in early machine check initialization to indicate that any errors found should just be queued to genpool. When mcheck_late_init() is called it will call mce_schedule_work() to actually log and flush any errors queued in the genpool. [ Based on an original patch, commit message by and completely productized by Tony Luck. ] Fixes: 5de97c9f6d85 ("x86/mce: Factor out and deprecate the /dev/mcelog driver") Reported-by: Sumanth Kamatala Signed-off-by: Borislav Petkov Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210824003129.GA1642753@agluck-desk2.amr.corp.intel.com Signed-off-by: Sasha Levin --- arch/x86/include/asm/mce.h | 1 + arch/x86/kernel/cpu/mce/core.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h index 0607ec4f5091..da9321548f6f 100644 --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -265,6 +265,7 @@ enum mcp_flags { MCP_TIMESTAMP = BIT(0), /* log time stamp */ MCP_UC = BIT(1), /* log uncorrected errors */ MCP_DONTLOG = BIT(2), /* only clear, don't log */ + MCP_QUEUE_LOG = BIT(3), /* only queue to genpool */ }; bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b); diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 22791aadc085..8cb7816d03b4 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -817,7 +817,10 @@ log_it: if (mca_cfg.dont_log_ce && !mce_usable_address(&m)) goto clear_it; - mce_log(&m); + if (flags & MCP_QUEUE_LOG) + mce_gen_pool_add(&m); + else + mce_log(&m); clear_it: /* @@ -1639,10 +1642,12 @@ static void __mcheck_cpu_init_generic(void) m_fl = MCP_DONTLOG; /* - * Log the machine checks left over from the previous reset. + * Log the machine checks left over from the previous reset. Log them + * only, do not start processing them. That will happen in mcheck_late_init() + * when all consumers have been registered on the notifier chain. */ bitmap_fill(all_banks, MAX_NR_BANKS); - machine_check_poll(MCP_UC | m_fl, &all_banks); + machine_check_poll(MCP_UC | MCP_QUEUE_LOG | m_fl, &all_banks); cr4_set_bits(X86_CR4_MCE); -- 2.30.2