From owner-freebsd-hackers@FreeBSD.ORG Thu Oct 7 16:29:15 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B554E16A4CE for ; Thu, 7 Oct 2004 16:29:15 +0000 (GMT) Received: from hanoi.cronyx.ru (hanoi.cronyx.ru [144.206.181.53]) by mx1.FreeBSD.org (Postfix) with ESMTP id 159AF43D1F for ; Thu, 7 Oct 2004 16:29:09 +0000 (GMT) (envelope-from rik@cronyx.ru) Received: (from root@localhost) by hanoi.cronyx.ru id i97GQ6uL088744 for hackers@FreeBSD.org.checked; (8.12.8/vak/2.1) Thu, 7 Oct 2004 20:26:06 +0400 (MSD) (envelope-from rik@cronyx.ru) Received: from cronyx.ru (hi.cronyx.ru [144.206.181.94]) by hanoi.cronyx.ru with ESMTP id i97GJdKG088495; (8.12.8/vak/2.1) Thu, 7 Oct 2004 20:23:40 +0400 (MSD) (envelope-from rik@cronyx.ru) Message-ID: <41656D4A.3030406@cronyx.ru> Date: Thu, 07 Oct 2004 20:22:34 +0400 From: Roman Kurakin User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.6b) Gecko/20031208 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Don Lewis References: <200410062324.i96NOc4b056930@gw.catspoiler.org> In-Reply-To: <200410062324.i96NOc4b056930@gw.catspoiler.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit cc: hackers@FreeBSD.org Subject: Re: Printing from kernel X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Oct 2004 16:29:15 -0000 Don Lewis wrote: >On 7 Oct, Roman Kurakin wrote: > > >>Hi, >> >> I have some problems with printing from kernel. >>At first I think that my problems was cause I use printf, >>but changed all of them to log cause it safe to use from >>interrupt handlers. The situation become better but I still >>observe system lockup in case I output some debug information >>from my driver. >> >> Also I have some problems with system console via com >>port. Instead of messages from kernel I see the first letter >>of the month name. >> >> > >This is a bug in syslogd related to non-blocking I/O that bde and I >discussed quite a while back, though we never figured out a proper fix. >I recently made the interesting discovery that the same problem isn't >present on sparc64. > >I think it'll start working again if you restart syslogd. > > From my observation I didn't came to conclusion that this could be due to syslog, but I'll check this. >> Could anybody comment my observation? Does anybody >>saw anything like this? >> >> Oh, I forget to say I observe that with both Current >>and Releng5, SMP. Also I can't trigger NMI so I can't see the >>point of lockup. >> >> > >I generally use printf for this sort of thing, and I was going to >suggest that you take a look at the KTR stuff, but that won't help if >the machine totally locks up so that you can't get to the KTR buffer. > >I think you'll have trouble getting close to the bug if you use log >because of the log latency from the generation of the message, passing >it through syslogd, and back to the kernel to be printed. > > I'll try to think up how to see where I have my problems. If you plan to work on this problems we could join our efforts, rik >_______________________________________________ >freebsd-hackers@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-hackers >To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > > > >