From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933239AbYBNM0E (ORCPT ); Thu, 14 Feb 2008 07:26:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757548AbYBNMZy (ORCPT ); Thu, 14 Feb 2008 07:25:54 -0500 Received: from slowhand.arndnet.de ([88.198.19.76]:37357 "EHLO mail.unitix.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755632AbYBNMZx (ORCPT ); Thu, 14 Feb 2008 07:25:53 -0500 Message-ID: <47B433C8.3030301@i4.informatik.rwth-aachen.de> Date: Thu, 14 Feb 2008 13:27:52 +0100 From: Arnd Hannemann User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Hans-Peter Jansen CC: linux-kernel@vger.kernel.org Subject: Re: strange SysRq problem References: <200802140102.14252.hpj@urpla.net> In-Reply-To: <200802140102.14252.hpj@urpla.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hans-Peter Jansen wrote: > I'm suffering from a strange SysRq problem: > > syslog shows haphazardly "SysRq : HELP" lines, while I definitely didn't > triggered them, neither via (PS/2) keyboard, nor via /proc/sysrq-trigger. > This is accompanied with stalls of about 15-60 secs. Any chance that a device connected via serial (or an USB device which uses USB/Serial conversion) triggers them? My cheap pl2303 device seems to send spurious BREAKs every once in a while, which results in the described behavior, as the kernel will print the help line for any character which is not a valid sysrq. (The probability to trigger another sysrq with random data is much lower, but did you find any other printout of an sysrq in your logs?) Best regards, Arnd Hannemann