Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753025AbbLNIS7 (ORCPT ); Mon, 14 Dec 2015 03:18:59 -0500 Received: from terminus.zytor.com ([198.137.202.10]:52309 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752952AbbLNISy (ORCPT ); Mon, 14 Dec 2015 03:18:54 -0500 Date: Mon, 14 Dec 2015 00:18:19 -0800 From: tip-bot for Ashok Raj Message-ID: Cc: tony.luck@intel.com, torvalds@linux-foundation.org, ashok.raj@intel.com, mingo@kernel.org, stable@vger.kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de, linux-edac@vger.kernel.org, bp@suse.de Reply-To: torvalds@linux-foundation.org, ashok.raj@intel.com, tony.luck@intel.com, stable@vger.kernel.org, mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de, linux-edac@vger.kernel.org, bp@suse.de In-Reply-To: <1449742346-21470-2-git-send-email-bp@alien8.de> References: <1449742346-21470-2-git-send-email-bp@alien8.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mce: Ensure offline CPUs don' t participate in rendezvous process Git-Commit-ID: 06f337b7c7eb86254c86e8e717273d1e356d5a1b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2682 Lines: 73 Commit-ID: 06f337b7c7eb86254c86e8e717273d1e356d5a1b Gitweb: http://git.kernel.org/tip/06f337b7c7eb86254c86e8e717273d1e356d5a1b Author: Ashok Raj AuthorDate: Thu, 10 Dec 2015 11:12:26 +0100 Committer: Ingo Molnar CommitDate: Fri, 11 Dec 2015 08:59:48 +0100 x86/mce: Ensure offline CPUs don't participate in rendezvous process Intel's MCA implementation broadcasts MCEs to all CPUs on the node. This poses a problem for offlined CPUs which cannot participate in the rendezvous process: Kernel panic - not syncing: Timeout: Not all CPUs entered broadcast exception handler Kernel Offset: disabled Rebooting in 100 seconds.. More specifically, Linux does a soft offline of a CPU when writing a 0 to /sys/devices/system/cpu/cpuX/online, which doesn't prevent the #MC exception from being broadcasted to that CPU. Ensure that offline CPUs don't participate in the MCE rendezvous and clear the RIP valid status bit so that a second MCE won't cause a shutdown. Without the patch, mce_start() will increment mce_callin and wait for all CPUs. Offlined CPUs should avoid participating in the rendezvous process altogether. Signed-off-by: Ashok Raj [ Massage commit message. ] Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Cc: Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-edac Link: http://lkml.kernel.org/r/1449742346-21470-2-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/mcheck/mce.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index c5b0d56..7e8a736 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -999,6 +999,17 @@ void do_machine_check(struct pt_regs *regs, long error_code) int flags = MF_ACTION_REQUIRED; int lmce = 0; + /* If this CPU is offline, just bail out. */ + if (cpu_is_offline(smp_processor_id())) { + u64 mcgstatus; + + mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS); + if (mcgstatus & MCG_STATUS_RIPV) { + mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); + return; + } + } + ist_enter(regs); this_cpu_inc(mce_exception_count); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/