From owner-freebsd-questions@FreeBSD.ORG Mon Feb 25 13:44:31 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 655E816A403 for ; Mon, 25 Feb 2008 13:44:31 +0000 (UTC) (envelope-from yoniy@mellanox.co.il) Received: from mellanox.co.il (mail.mellanox.co.il [194.90.237.43]) by mx1.freebsd.org (Postfix) with ESMTP id A2AF813C4CE for ; Mon, 25 Feb 2008 13:44:30 +0000 (UTC) (envelope-from yoniy@mellanox.co.il) Received: from Internal Mail-Server by MTLPINE1 (envelope-from yoniy@mellanox.co.il) with SMTP; 25 Feb 2008 15:44:29 +0200 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-MimeOLE: Produced By Microsoft Exchange V6.5 Date: Mon, 25 Feb 2008 15:44:28 +0200 Message-ID: <6C2C79E72C305246B504CBA17B5500C90364164C@mtlexch01.mtl.com> In-Reply-To: <200802251436.32206.fbsd.questions@rachie.is-a-geek.net> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Capturing dmesg upon system crash on 6.3 Thread-Index: Ach3s4piuKUOpBwvRz+PrujUo8aq9AAAIn1g From: "Yehonatan Yossef" To: "Mel" , Cc: Subject: RE: Capturing dmesg upon system crash on 6.3 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Feb 2008 13:44:31 -0000 > On Monday 25 February 2008 13:32:01 Yehonatan Yossef wrote: > > > > I'm facing a system reboot upon loading of the driver, and > > > > > > I could use > > > > > > > a tool for capturing dmesg upon system crash (such as=20 > netconsole=20 > > > > on Linux). > > > > > > Your kernel isn't setup for driver development: > > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-ha > > > ndbook/kerneldebug.html > > > http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kern > > > elconfig.html > > > > > > Basically, your system is rebooting cause the kernel panics and=20 > > > you're not setup for crash dumps, or anything that could help you=20 > > > diagnose the panic. > > > -- > > > Mel > > > > I've setup the dumpdev/dumpdir and I get a vmcore image=20 > upon a crash. > > > > I don't really understand how to use kgdb in order to read=20 > it but more=20 > > than that - I don't need that much of data. I only want the dmesg=20 > > report at the moment, see at what point my driver went=20 > crazy. Is it possible? >=20 >=20 > Uhm, no. Fundamental logic flaw: when a kernel is stopped,=20 > you can't issue userland commands. All you have when you use=20 > ddb, is the contents of the registers, ram and backtrace. >=20 > You really want ddb in the kernel: when a kernel panics,=20 > it'll drop to ddb and you can examine registers and do a=20 > backtrace, instead of dumping core and rebooting. It should=20 > point exactly to where your driver went crazy. > -- > Mel >=20 I meant making the dmesg log sent over the network/serial console to a linux machine. I just found out about syslogd, I'm trying to figure out how to use it. DDB sounds like a great option for deeper debugging, I'll use it. Yony