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Debugging the FreeBSD Kernel Transparently

Posted by kdawson on from the deep-juju dept.

An anonymous reader writes "To debug the FreeBSD kernel core dump efficiently, it is best to set up a remote debugging session between a development machine and the target machine, and remotely debug the kernel using serial communication. This article shows you how you can debug as many kernel images as you want; it becomes transparent to users once debugging starts, and your system's performance is not affected at all."

5 of 55 comments (clear)

  1. Surely... by BluhDeBluh · · Score: 4, Funny

    If this news day gets any slower it's just going to just stop.

  2. I was just about to post this story.... by concernedadmin · · Score: 3, Informative

    Hehe, good to see others saw this as an influential story of the day.
    However, I have a question that perhaps others can answer.
    What does the diagram actually work out?
    Listing 1. 25-Pin NULL modem cabling

    2 3 Transmit Data
    3 2 Receive Data
    4 5 Request to Send
    5 4 Clear to Send
    6 20 Data Set Ready and Carrier Detect
    7 7 Signal Ground
    20 6 Data Terminal Ready

    What does that mean? I thought serial -> serial is merely a connection. Do I have to solder something?

    Regards

    1. Re:I was just about to post this story.... by ampmouse · · Score: 4, Informative

      What does the diagram actually work out?
      This is a Null modem adapter. It allows you to connect to terminals, such as computers, together without a modem. It is the serial equivalent of a ethernet crossover cable.
  3. Unfortunately by edderly · · Score: 3, Funny

    Jayesh V. Rane works as a Systems Software Engineer for IBM and has five years of experience in product development, mostly working on network programming and storage management software. He has worked extensively on FreeBSD and AIX operating systems. Jayesh is currently working with the IBM India Systems and Technology Lab in Pune, India. You can contact him at jayesh.rane@in.ibm.com. Unfortunately Jayesh doesn't understand that compiling your kernel with -g will in fact affect the systems performance and is currently looking for a job where he can pretend to be a kernel engineer. Contact Jayesh at jayesh.rane@aol.com

  4. Wyse terminals work well for this. by Anonymous Coward · · Score: 3, Interesting

    About 5 years ago I used an old Wyse terminal I got at a junkyard for exactly this job using a homemade cable, it worked beautifully. Once complete I then used the terminal to control and update the server from the living room couch.

    I also used the same terminal and SoftIce to *ahem* "debug" several windows applications.

    Wyse terminals (at least the older ones) are excellent gear, very sturdy, nice keyboards, though the monochrome monitor was a bit burnt in on the one I used. An industrial strength terminal for a rock solid OS. A match made in heaven. FreeBSD is an excellent OS.