From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752603AbbHMKsg (ORCPT ); Thu, 13 Aug 2015 06:48:36 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53003 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752286AbbHMKse (ORCPT ); Thu, 13 Aug 2015 06:48:34 -0400 Date: Thu, 13 Aug 2015 03:47:24 -0700 From: "tip-bot for Chen, Gong" Message-ID: Cc: gong.chen@linux.intel.com, bp@suse.de, tglx@linutronix.de, xiexiuqi@huawei.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tony.luck@intel.com, torvalds@linux-foundation.org, peterz@infradead.org, mingo@kernel.org Reply-To: peterz@infradead.org, mingo@kernel.org, tony.luck@intel.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, hpa@zytor.com, xiexiuqi@huawei.com, tglx@linutronix.de, gong.chen@linux.intel.com, bp@suse.de In-Reply-To: <1439396985-12812-6-git-send-email-bp@alien8.de> References: <1439396985-12812-6-git-send-email-bp@alien8.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:ras/core] x86/mce: Avoid potential deadlock due to printk() in MCE context Git-Commit-ID: f29a7aff4bd60ebc3da4982f80144a4158c4c74a 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 Commit-ID: f29a7aff4bd60ebc3da4982f80144a4158c4c74a Gitweb: http://git.kernel.org/tip/f29a7aff4bd60ebc3da4982f80144a4158c4c74a Author: Chen, Gong AuthorDate: Wed, 12 Aug 2015 18:29:37 +0200 Committer: Ingo Molnar CommitDate: Thu, 13 Aug 2015 10:12:51 +0200 x86/mce: Avoid potential deadlock due to printk() in MCE context Printing in MCE context is a no-no, currently, as printk() is not NMI-safe. If some of the notifiers on the MCE chain call do so, we may deadlock. In order to avoid that, delay printk() to process context where it is safe. Reported-by: Xie XiuQi Signed-off-by: Chen, Gong [ Fold in subsequent patch from Boris for early boot logging. ] Signed-off-by: Tony Luck [ Kick irq_work in mce_log() directly. ] Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1439396985-12812-6-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/mcheck/mce-apei.c | 1 - arch/x86/kernel/cpu/mcheck/mce.c | 4 ++-- arch/x86/kernel/cpu/mcheck/mce_intel.c | 1 - 3 files changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce-apei.c b/arch/x86/kernel/cpu/mcheck/mce-apei.c index a1aef95..34c89a3 100644 --- a/arch/x86/kernel/cpu/mcheck/mce-apei.c +++ b/arch/x86/kernel/cpu/mcheck/mce-apei.c @@ -57,7 +57,6 @@ void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err) m.addr = mem_err->physical_addr; mce_log(&m); - mce_notify_irq(); } EXPORT_SYMBOL_GPL(apei_mce_report_mem_error); diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index 8260369..9568bb5 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -159,7 +159,8 @@ void mce_log(struct mce *mce) /* Emit the trace record: */ trace_mce_record(mce); - atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce); + if (!mce_gen_pool_add(mce)) + irq_work_queue(&mce_irq_work); mce->finished = 0; wmb(); @@ -1122,7 +1123,6 @@ void do_machine_check(struct pt_regs *regs, long error_code) /* assuming valid severity level != 0 */ m.severity = severity; m.usable_addr = mce_usable_address(&m); - mce_gen_pool_add(&m); mce_log(&m); diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c index 844f56c..70f567f 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_intel.c +++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c @@ -246,7 +246,6 @@ static void intel_threshold_interrupt(void) return; machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_banks_owned)); - mce_notify_irq(); } /*