Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753603AbbLCXQO (ORCPT ); Thu, 3 Dec 2015 18:16:14 -0500 Received: from mga01.intel.com ([192.55.52.88]:64724 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097AbbLCXQN (ORCPT ); Thu, 3 Dec 2015 18:16:13 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,378,1444719600"; d="scan'208";a="699838547" From: Ashok Raj To: linux-kernel@vger.kernel.org Cc: Ashok Raj , stable@vger.kernel.org, linux-edac@vger.kernel.org, Boris Petkov , Tony Luck Subject: [Patch V0] x86, mce: Ensure offline CPU's don't participate in mce rendezvous process. Date: Thu, 3 Dec 2015 19:16:10 -0500 Message-Id: <1449188170-3909-1-git-send-email-ashok.raj@intel.com> X-Mailer: git-send-email 2.4.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2254 Lines: 69 Linux has logical cpu offline capability. That can be triggered by: # echo 0 > /sys/devices/system/cpu/cpuX/online In Intel Architecture, MCE's are broadcasted to all CPUs in the system. This includes the CPUs marked offline by Linux. Unless the CPU's were removed via an ACPI notification, in which case the cpu's are removed from the cpu_present_map. This patch ensures offline CPU's don't participate in MCE rendezvous, but simply perform clearing some status bits to ensure a second MCE wont cause automatic shutdown. Without the patch, mce_start will increment mce_callin, but mce_start would wait for all online_cpus. So offline cpu's should avoid participating in the rendezvous process. Reviewed-by: Tony Luck Signed-off-by: Ashok Raj --- arch/x86/kernel/cpu/mcheck/mce.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index c5b0d56..82a0c8b 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -998,6 +998,7 @@ void do_machine_check(struct pt_regs *regs, long error_code) u64 recover_paddr = ~0ull; int flags = MF_ACTION_REQUIRED; int lmce = 0; + unsigned int cpu = smp_processor_id(); ist_enter(regs); @@ -1008,6 +1009,14 @@ void do_machine_check(struct pt_regs *regs, long error_code) mce_gather_info(&m, regs); + /* + * if this cpu is offline, just bail out. + * TBD: looking into adding any logs this offline CPU might have, + * to be collected and reported by the rendezvous master. + */ + if (cpu_is_offline(cpu) && (m.mcgstatus & MCG_STATUS_RIPV)) + goto out; + final = this_cpu_ptr(&mces_seen); *final = m; @@ -1142,8 +1151,8 @@ void do_machine_check(struct pt_regs *regs, long error_code) if (worst > 0) mce_report_event(regs); - mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); out: + mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); sync_core(); if (recover_paddr == ~0ull) -- 2.4.3 -- 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/