Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751509AbaLEPDc (ORCPT ); Fri, 5 Dec 2014 10:03:32 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:18657 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750920AbaLEPDa (ORCPT ); Fri, 5 Dec 2014 10:03:30 -0500 Message-ID: <5481C92E.6020805@oracle.com> Date: Fri, 05 Dec 2014 10:03:10 -0500 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Linus Torvalds CC: Dave Jones , Chris Mason , =?UTF-8?B?RMOibmllbCBGcmFnYQ==?= , "Paul E. McKenney" , Linux Kernel Mailing List Subject: Re: frequent lockups in 3.18rc4 References: <20141127225637.GA24019@redhat.com> <547b8a45.6e608c0a.20f9.1002@mx.google.com> <547bbe36.48548c0a.105c.779c@mx.google.com> <20141201191431.GA17385@linux.vnet.ibm.com> <547ccf74.a5198c0a.25de.26d9@mx.google.com> <20141201230339.GA20487@ret.masoncoding.com> <20141202193252.GB17595@redhat.com> <547E4C14.6040509@oracle.com> <54813C03.8040009@oracle.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/05/2014 01:38 AM, Linus Torvalds wrote: > On Thu, Dec 4, 2014 at 9:00 PM, Sasha Levin wrote: >> > >> > Just to add to this: I've enabled the simplest level of verbosity in the fault >> > injection options, and RCU stalls are again easy to trigger: > Where do you log to? > > In particular, do you have some serial line logging enabled (perhaps > even without anybody listening)? Or network logging? > > We've definitely had cases where logging itself is so slow that it > triggers watchdogs etc. Logging to a serial line can take for*ever* in > modern terms.. Yes, it's going to a serial line, but it's only about 100 lines/second on average. I wouldn't expect it to cause anything to hang! Thanks, Sasha -- 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/