From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:40643 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753986AbcAYAAM (ORCPT ); Sun, 24 Jan 2016 19:00:12 -0500 Subject: Patch "x86/mce: Ensure offline CPUs don't participate in rendezvous process" has been added to the 4.3-stable tree To: ashok.raj@intel.com, bp@suse.de, gregkh@linuxfoundation.org, hpa@zytor.com, linux-edac@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, tony.luck@intel.com, torvalds@linux-foundation.org Cc: , From: Date: Sun, 24 Jan 2016 16:00:06 -0800 Message-ID: <1453680006113204@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled x86/mce: Ensure offline CPUs don't participate in rendezvous process to the 4.3-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-mce-ensure-offline-cpus-don-t-participate-in-rendezvous-process.patch and it can be found in the queue-4.3 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From d90167a941f62860f35eb960e1012aa2d30e7e94 Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Thu, 10 Dec 2015 11:12:26 +0100 Subject: x86/mce: Ensure offline CPUs don't participate in rendezvous process From: Ashok Raj commit d90167a941f62860f35eb960e1012aa2d30e7e94 upstream. 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: 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 Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mcheck/mce.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- 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 *re 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); Patches currently in stable-queue which might be from ashok.raj@intel.com are queue-4.3/x86-mce-ensure-offline-cpus-don-t-participate-in-rendezvous-process.patch