Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761401Ab2EJSjr (ORCPT ); Thu, 10 May 2012 14:39:47 -0400 Received: from mga11.intel.com ([192.55.52.93]:20978 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761009Ab2EJSjp (ORCPT ); Thu, 10 May 2012 14:39:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="164574284" Message-Id: In-Reply-To: References: From: Tony Luck Date: Thu, 10 May 2012 11:01:20 -0700 Subject: [PATCH 1/2] x86/mce: Only restart instruction after machine check recovery if it is safe MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Borislav Petkov , Chen Gong , "Huang, Ying" , Hidetoshi Seto Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2519 Lines: 69 Section 15.3.1.2 of the software developer manual has this to say about the RIPV bit in the IA32_MCG_STATUS register: RIPV (restart IP valid) flag, bit 0 — Indicates (when set) that program execution can be restarted reliably at the instruction pointed to by the instruction pointer pushed on the stack when the machine-check exception is generated. When clear, the program cannot be reliably restarted at the pushed instruction pointer. We need to save the state of this bit in do_machine_check() and use it in mce_notify_process() to force a signal; even if memory_failure() says it made a complete recovery ... e.g. replaced a clean LRU page). Signed-off-by: Tony Luck --- arch/x86/kernel/cpu/mcheck/mce.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 66e1c51..3b8ebdc 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -947,9 +947,10 @@ struct mce_info { atomic_t inuse; struct task_struct *t; __u64 paddr; + int restartable; } mce_info[MCE_INFO_MAX]; -static void mce_save_info(__u64 addr) +static void mce_save_info(__u64 addr, int c) { struct mce_info *mi; @@ -957,6 +958,7 @@ static void mce_save_info(__u64 addr) if (atomic_cmpxchg(&mi->inuse, 0, 1) == 0) { mi->t = current; mi->paddr = addr; + mi->restartable = c; return; } } @@ -1136,7 +1138,7 @@ void do_machine_check(struct pt_regs *regs, long error_code) mce_panic("Fatal machine check on current CPU", &m, msg); if (worst == MCE_AR_SEVERITY) { /* schedule action before return to userland */ - mce_save_info(m.addr); + mce_save_info(m.addr, m.mcgstatus & MCG_STATUS_RIPV); set_thread_flag(TIF_MCE_NOTIFY); } else if (kill_it) { force_sig(SIGBUS, current); @@ -1185,7 +1187,8 @@ void mce_notify_process(void) pr_err("Uncorrected hardware memory error in user-access at %llx", mi->paddr); - if (memory_failure(pfn, MCE_VECTOR, MF_ACTION_REQUIRED) < 0) { + if (memory_failure(pfn, MCE_VECTOR, MF_ACTION_REQUIRED) < 0 || + mi->restartable == 0) { pr_err("Memory error not recovered"); force_sig(SIGBUS, current); } -- 1.7.9.rc2.1.g69204 -- 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/