Date: Wed, 23 Oct 2002 11:12:19 -0600 (MDT) From: Fred Clift <fclift@verio.net> To: <freebsd-alpha@freebsd.org> Subject: debugging around machine-checks... Message-ID: <20021023110134.Q98807-100000@vespa.dmz.orem.verio.net>
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Ok -- I'm not terribly alpha proficitent - in fact, the one alpha that I run is just a home-server - little more than a toy (mp3 server, print server and relatively secure ssh enpoint from the outside world). Could someone explain exactly what is going on when a machine-check happens? Is this done by the machine firmware or something? It seems that FreeBSD is instantenously interrupted when a machine check happens and that I dont get crash-dumps. Some of you may recall that I've been playing around with XFree86 V4 on this box - it would be exceptionally helpful if I got usable crash-dumps instead of machine checks when things got wierd. As it is, debugging the X server is pretty much impossible (for me) because of this. What I've done is build all of the X distribution with debugging symbols in and then I start the X server from gdb and put in 10 break points near where I think things will be happening. Eventually, I get a machine check and if I'm lucky, I remember where the last breakpoint that I hit was so that after a reboot, I can kind of start back in that neighborhood. X is hard enough to debug by itself without this inconvienence. It seems that whatever is making it machine-check should be things that could be fixed in the kernel, at which point, my debugging of the X server could then continue.Then when X dumps core I can just restart X rather than wait for a reboot/fsck. Am I way off here? I seem to have read somewhere that there is something you can do to fend off machine-checks so that you can get a proper crash-dump? What is the mechanism that causes the checks and how bad would it be for the system to do something equivalent to maksing these events out (or whatever you'd do to get them to not happen?). Is there somewhere I can read about this? Fred -- Fred Clift - fclift@verio.net -- Remember: If brute force doesn't work, you're just not using enough. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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