From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932721AbYBNO22 (ORCPT ); Thu, 14 Feb 2008 09:28:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754827AbYBNO2U (ORCPT ); Thu, 14 Feb 2008 09:28:20 -0500 Received: from moutng.kundenserver.de ([212.227.126.188]:64932 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754787AbYBNO2T (ORCPT ); Thu, 14 Feb 2008 09:28:19 -0500 From: Hans-Peter Jansen To: linux-kernel@vger.kernel.org Subject: Re: strange SysRq problem Date: Thu, 14 Feb 2008 15:28:11 +0100 User-Agent: KMail/1.9.6 (enterprise 20071221.751182) Cc: Arnd Hannemann References: <200802140102.14252.hpj@urpla.net> <47B433C8.3030301@i4.informatik.rwth-aachen.de> In-Reply-To: <47B433C8.3030301@i4.informatik.rwth-aachen.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200802141528.11519.hpj@urpla.net> X-Provags-ID: V01U2FsdGVkX199YzaG3CECdKi6apWOpXMKIDg745dN6yLFyiS H6+o/g46ijLTOXLsHJZKzxHg7YFhlaPOkjWlNIzW05ut8Co/CS sRSdJADVWTfAi0rz+Y/Bw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Donnerstag, 14. Februar 2008 schrieb Arnd Hannemann: > 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?) Hmm, keyboard (Cherry G80-3000 LPCDE-2) and mouse (Logitech RX300) are connected via an equip KVM 2 port switch, but everything else is behaving properly, and no serial devices connected ATM. It only triggers the help messages, other sysrq messages are triggered at will (AFAIKS). # grep "SysRq : HELP" /var/log/messages | wc -l 814 syslog starts at Jan 16, so you can imagine how disturbing this behavior is. I cannot outrule some hardware defects. Will start to eliminate the KVM switch, but I thought, I ask here before since google also didn't revealed any hints.. Thanks, Pete