Date: Wed, 26 Nov 2003 11:30:10 +1030 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Kent Kuriyama <kuriyama@newhost.cpf.navy.mil> Cc: questions@FreeBSD.org Subject: Re: Questions regarding use of 'gdb -k' Message-ID: <20031126010009.GT82843@wantadilla.lemis.com> In-Reply-To: <200311240426.hAO4QcU5041986@newhost.cpf.navy.mil> References: <20031124031246.GW82843@wantadilla.lemis.com> <200311240426.hAO4QcU5041986@newhost.cpf.navy.mil>
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--sFDE4zCwgxz4NHeP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sunday, 23 November 2003 at 18:26:38 -1000, Kent Kuriyama wrote: >> On Sunday, 23 November 2003 at 17:02:09 -1000, Kent Kuriyama wrote: >>> I am having difficulty in using 'gdb -k' to track down a kernel panic. I >>> have built a version of the kernel with the debugging symbols. After >>> the crash I use the 'gdb -k' command but get the following output: >>> .... >>> IdlePTD at phsyical address 0x00000000 >>> initial pcb at physical address 0x0048cee0 >>> >>> cannot read proc at 0 >>> (kgdb) where >>> #0 0x0 in ?? () >>> (kgdb) exit >>> Undefined command: "exit". Try "help". >>> (kgdb) chinmon1# >>> ------------------ >>> >>> Can you tell me what I am doing wrong? Thanks. >> >> Unfortunately, this looks like you have a corrupted dump. What you've >> done (with the exception of "exit") is correct. You might find it >> better to use serial debugging if this is repeatable. > > Thanks. Regarding the suspected corrupt dump file. In the syslog I can > see the dump file being created (actually 'vmcore') and there are no > error messages. Are you saying that the corruption occurs during > the writing of the file or is the data resident in memory corrupt? I suspect that the problem is that the contents of memory are so scrambled that you can't do much with them. I get this kind of problem from time to time. The whole purpose of having a dump is to find out what went wrong on the system. If it goes too far wrong, there's nothing much left to see. You could try debugging over a serial link. > I suspect that something is wrong with the hardware on this box. We > moved the hard drive from one motherboard to another but the problem > remains. This leaves the hard drive as suspect but there are no > syslog messages to indicate a drive problem. You won't get syslog messages when the system crashes. You could look in msgbuf and see if there's any clue there: # msgbuf: print msgbuf. Can take forever. define msgbuf printf "%s", msgbufp->msg_ptr end document msgbuf Print the system message buffer (dmesg). This can take a long time due to the time it takes to transmit the data across a serial line. end Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply or reply to the original recipients. For more information, see http://www.lemis.com/questions.html See complete headers for address and phone numbers. --sFDE4zCwgxz4NHeP Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQE/w/sZIubykFB6QiMRAhDfAKCF4PLdVu95E1UXTQfumm7EhhxwVwCgtHJi y7pkLJ0hP8gLcKcphnIOJk0= =UPh3 -----END PGP SIGNATURE----- --sFDE4zCwgxz4NHeP--
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