From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH v3 4/9] ACPI, x86: Extended error log driver for x86 platform Date: Fri, 27 Jun 2014 11:22:27 +0200 Message-ID: <20140627092227.GA23153@pd.tnic> References: <1382084624-10857-1-git-send-email-gong.chen@linux.intel.com> <1382084624-10857-5-git-send-email-gong.chen@linux.intel.com> <52612BA4.2060906@linux.vnet.ibm.com> <53AD0275.7020003@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Received: from mail.skyhub.de ([78.46.96.112]:56291 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751127AbaF0JWe (ORCPT ); Fri, 27 Jun 2014 05:22:34 -0400 Content-Disposition: inline In-Reply-To: <53AD0275.7020003@huawei.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Xie XiuQi Cc: "Naveen N. Rao" , "Chen, Gong" , tony.luck@intel.com, joe@perches.com, m.chehab@samsung.com, arozansk@redhat.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Li Bin On Fri, Jun 27, 2014 at 01:34:45PM +0800, Xie XiuQi wrote: > The call graph is like this, > do_machine_check > -> mce_log > -> atomic_notifier_call_chain(&x86_mce_decoder_chain ...) > -> ... > -> extlog_print > -> print_extlog_rcd > -> __print_extlog_rcd > -> printk > > There's a logbuf_lock in printk. If logbuf_lock is held by other cpu, > it'll lead to an infinity spin here. Isn't it? Yes, but we want to take the risk and print something out before the machine dies instead of waiting to get into printk-safe context first and maybe corrupt state. Besides, there's work currently going on to make printk safe in atomic context so... -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --