From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753229AbdKSPAm (ORCPT ); Sun, 19 Nov 2017 10:00:42 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54220 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752462AbdKSPAh (ORCPT ); Sun, 19 Nov 2017 10:00:37 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yazen Ghannam , Borislav Petkov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Tony Luck , linux-edac , Ingo Molnar Subject: [PATCH 4.14 19/31] x86/MCE/AMD: Always give panic severity for UC errors in kernel context Date: Sun, 19 Nov 2017 15:59:53 +0100 Message-Id: <20171119145951.907951492@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171119145951.136379453@linuxfoundation.org> References: <20171119145951.136379453@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yazen Ghannam commit d65dfc81bb3894fdb68cbc74bbf5fb48d2354071 upstream. The AMD severity grading function was introduced in kernel 4.1. The current logic can possibly give MCE_AR_SEVERITY for uncorrectable errors in kernel context. The system may then get stuck in a loop as memory_failure() will try to handle the bad kernel memory and find it busy. Return MCE_PANIC_SEVERITY for all UC errors IN_KERNEL context on AMD systems. After: b2f9d678e28c ("x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries") was accepted in v4.6, this issue was masked because of the tail-end attempt at kernel mode recovery in the #MC handler. However, uncorrectable errors IN_KERNEL context should always be considered unrecoverable and cause a panic. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Fixes: bf80bbd7dcf5 (x86/mce: Add an AMD severities-grading function) Link: http://lkml.kernel.org/r/20171106174633.13576-1-bp@alien8.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mcheck/mce-severity.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/arch/x86/kernel/cpu/mcheck/mce-severity.c +++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c @@ -245,6 +245,9 @@ static int mce_severity_amd(struct mce * if (m->status & MCI_STATUS_UC) { + if (ctx == IN_KERNEL) + return MCE_PANIC_SEVERITY; + /* * On older systems where overflow_recov flag is not present, we * should simply panic if an error overflow occurs. If @@ -255,10 +258,6 @@ static int mce_severity_amd(struct mce * if (mce_flags.smca) return mce_severity_amd_smca(m, ctx); - /* software can try to contain */ - if (!(m->mcgstatus & MCG_STATUS_RIPV) && (ctx == IN_KERNEL)) - return MCE_PANIC_SEVERITY; - /* kill current process */ return MCE_AR_SEVERITY; } else {