Date: Thu, 31 Dec 1998 12:17:31 +1030 From: Greg Lehey <grog@lemis.com> To: Alan Jones <jones@veritas.com>, freebsd-questions@FreeBSD.ORG Subject: Re: hung system Message-ID: <19981231121731.K32696@freebie.lemis.com> In-Reply-To: <m0zvX4z-0000gqC@megami.veritas.com>; from Alan Jones on Wed, Dec 30, 1998 at 05:39:12PM -0800 References: <m0zvX4z-0000gqC@megami.veritas.com>
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On Wednesday, 30 December 1998 at 17:39:12 -0800, Alan Jones wrote: > Hello, > > I've done kernel development on a variety of Unix systems. What I > have appears to be a hung system. Same symtom on 2.2.7 & 2.2.8. I've > got kernel ppp configured (user-level would not work for me) What happened? > on a USR03030 Sportster X2 mumble. It is a 333 Pentium from Micron. > Everything works until I stress the modem, for example, by ftp'ing a > large file. I've eliminated X software by reproducing it on the > text console. All things appear to hang, though I don't have a > network to check it for life over the net. > > What I would like to do is interupt the system and get a thread list > or stack from the thread the CPU is on. UnixWare has a kernel > debugger that you can use directly on the console and an interupt > keyboard sequence. I've put in the options DDB and BREAK_TO_ > DEBUGGER, however, p. 255 of "The Complete FreeBSD" indicates that > BREAK_TO_DEBUGGER only works if you have the console redirected to a > serial port. It's supposed to imply that it's only *needed* if you have a serial port. > I don't happen to have a VT100 handy and configuring my Pilot to act > as one is a lot of work just to run the debugger. ddb works just fine on the standard console. Use Ctrl-Alt-Esc to enter it. My only concern is that it might not be easy for you to find out what the problem is. ddb isn't the world's best kernel debugger. There is no threading in FreeBSD, and ddb can't even give you a stack trace from another process. In the case of a hang, you'll probably find a trace back to the idle process, which doesn't tell you very much. You might get a little more out of kernel gdb. Build a debug kernel, described on page 272-273, take a dump, described on page 87-88, and use gdb -k to debug it, as described in the online handbook, chapter 22 and http://www.lemis.com/vinum_debugging.html. This is an unusual problem. Is there anything unusual about your configuration? Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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