Serial port access through terminal server on Solaris 10 - Solaris

This is a discussion on Serial port access through terminal server on Solaris 10 - Solaris ; Hi, I have a multi-processor Opteron system which has the latest Solaris Express Community Edition from OpenSolaris installed on it. The build is called sol-nv-b69-x86 (probably Nevada build 69). I am trying to set up kernel debugging using mdb -K. ...

+ Reply to Thread
Results 1 to 4 of 4

Thread: Serial port access through terminal server on Solaris 10

  1. Serial port access through terminal server on Solaris 10

    Hi,

    I have a multi-processor Opteron system which has the latest Solaris
    Express
    Community Edition from OpenSolaris installed on it. The build is
    called
    sol-nv-b69-x86 (probably Nevada build 69). I am trying to set up
    kernel debugging
    using mdb -K. Looks like this needs serial port access. I have access
    to serial port through
    a Lantronix terminal server. I see all the output (when the system
    boots up at least)
    from the system on to the serial port. (I connect using normal PuTTY)
    But looks like
    no input is accepted, or it does not respond to any input.

    Any special tips and / or suggestions ?

    Help appreciated..!!

    Thanks
    --Debashis


  2. Re: Serial port access through terminal server on Solaris 10

    On Sep 17, 11:55 pm, and...@cucumber.demon.co.uk (Andrew Gabriel)
    wrote:
    > In article <1190053950.606450.37...@g4g2000hsf.googlegroups.co m>,
    > Debashis Dutt writes:
    >
    > > Hi,

    >
    > > I have a multi-processor Opteron system which has the latest Solaris
    > > Express
    > > Community Edition from OpenSolaris installed on it. The build is
    > > called
    > > sol-nv-b69-x86 (probably Nevada build 69). I am trying to set up
    > > kernel debugging
    > > using mdb -K. Looks like this needs serial port access.

    >
    > Why do you think this?
    >
    > --
    > Andrew Gabriel
    > [email address is not usable -- followup in the newsgroup]


    Because, all the documentation that I have read says that if I
    have to debug a live kernel with execution control (like step through
    it)
    then the only way to do is by using kmdb (mdb -K). mdb -k (small case
    "k")
    provides certain amount of kernel debugging (analyze dumps etc) but
    does
    not provide execution control on the kernel.

    If I am to use mdb -K, (actually mdb -KF) from a non-console tty, then
    again
    it looks lile mdb can only talk to a serial console port. To
    facilitate this I boot the
    system with "-B console=ttya" in the "kernel" line of /boot/grub/
    menu.lst"
    and I am able to get all the boot messages on the serial console. But
    I do not
    get the login prompt, nor do I get any mdb prompt back when I start
    mdb.

    I am not sure what is going on. It will be really nice to have some
    pointers
    on this.

    Thanks
    --Debashis


  3. Re: Serial port access through terminal server on Solaris 10

    On Sep 18, 12:43 pm, and...@cucumber.demon.co.uk (Andrew Gabriel)
    wrote:
    > In article <1190139061.285426.177...@y42g2000hsy.googlegroups. com>,
    > Debashis Dutt writes:
    >
    >
    >
    > > On Sep 17, 11:55 pm, and...@cucumber.demon.co.uk (Andrew Gabriel)
    > > wrote:
    > >> In article <1190053950.606450.37...@g4g2000hsf.googlegroups.co m>,
    > >> Debashis Dutt writes:

    >
    > >> > Hi,

    >
    > >> > I have a multi-processor Opteron system which has the latest Solaris
    > >> > Express
    > >> > Community Edition from OpenSolaris installed on it. The build is
    > >> > called
    > >> > sol-nv-b69-x86 (probably Nevada build 69). I am trying to set up
    > >> > kernel debugging
    > >> > using mdb -K. Looks like this needs serial port access.

    >
    > >> Why do you think this?

    >
    > > Because, all the documentation that I have read says that if I
    > > have to debug a live kernel with execution control (like step through
    > > it)
    > > then the only way to do is by using kmdb (mdb -K). mdb -k (small case
    > > "k")
    > > provides certain amount of kernel debugging (analyze dumps etc) but
    > > does
    > > not provide execution control on the kernel.

    >
    > > If I am to use mdb -K, (actually mdb -KF) from a non-console tty, then
    > > again
    > > it looks lile mdb can only talk to a serial console port.

    >
    > Where did you get this from? It isn't true.
    > mdb -K works fine from the console on a PC keyboard/display.
    > (The -F is invalid with -K -- there's no process involved.)
    >
    > --
    > Andrew Gabriel
    > [email address is not usable -- followup in the newsgroup]


    Actually I am trying to access the console through a KVM
    aggregrator. No matter where I try to start mdb from either from
    the KVM display or from a ssh /. telnet session, I get the message
    that "mdb needs to be started with -F along with -K from a non-console
    tty."

    Thanks
    --Debashis


  4. Re: Serial port access through terminal server on Solaris 10

    On Sep 20, 10:17 am, and...@cucumber.demon.co.uk (Andrew Gabriel)
    wrote:
    > In article <1190303166.507743.238...@v29g2000prd.googlegroups. com>,
    > Debashis Dutt writes:
    >
    >
    >
    > > On Sep 18, 12:43 pm, and...@cucumber.demon.co.uk (Andrew Gabriel)
    > > wrote:
    > >> In article <1190139061.285426.177...@y42g2000hsy.googlegroups. com>,
    > >> Debashis Dutt writes:
    > >> > On Sep 17, 11:55 pm, and...@cucumber.demon.co.uk (Andrew Gabriel)
    > >> > wrote:
    > >> >> In article <1190053950.606450.37...@g4g2000hsf.googlegroups.co m>,
    > >> >> Debashis Dutt writes:
    > >> >> > Hi,
    > >> >> > I have a multi-processor Opteron system which has the latest Solaris
    > >> >> > Express
    > >> >> > Community Edition from OpenSolaris installed on it. The build is
    > >> >> > called
    > >> >> > sol-nv-b69-x86 (probably Nevada build 69). I am trying to set up
    > >> >> > kernel debugging
    > >> >> > using mdb -K. Looks like this needs serial port access.

    >
    > >> >> Why do you think this?

    >
    > >> > Because, all the documentation that I have read says that if I
    > >> > have to debug a live kernel with execution control (like step through
    > >> > it)
    > >> > then the only way to do is by using kmdb (mdb -K). mdb -k (small case
    > >> > "k")
    > >> > provides certain amount of kernel debugging (analyze dumps etc) but
    > >> > does
    > >> > not provide execution control on the kernel.

    >
    > >> > If I am to use mdb -K, (actually mdb -KF) from a non-console tty, then
    > >> > again
    > >> > it looks lile mdb can only talk to a serial console port.

    >
    > >> Where did you get this from? It isn't true.
    > >> mdb -K works fine from the console on a PC keyboard/display.
    > >> (The -F is invalid with -K -- there's no process involved.)

    >
    > > Actually I am trying to access the console through a KVM
    > > aggregrator. No matter where I try to start mdb from either from
    > > the KVM display or from a ssh /. telnet session, I get the message
    > > that "mdb needs to be started with -F along with -K from a non-console
    > > tty."

    >
    > You have to run mdb -K on the system console, because all
    > the subsequent input and output will go to the console, and
    > not the tty on which you happen to issue the mdb command. You
    > can't do this over an ssh session because the kernel will be
    > stopped the instant mdb starts, so ssh process, the IP stack,
    > the ethernet driver, and everything else required to make an
    > ssh session work will be stopped. The only things that still
    > run are the console driver (using a special polled driver
    > interface which spins in a CPU loop to prevent anything else
    > running) and the mdb kernel module itself (not the mdb command
    > you ran).
    >
    > The message you're seeing is because you aren't running mdb -K
    > on the console. I suspect the -F will overide this check, but
    > that's no use to you -- you have to run it on the console.
    >
    > --
    > Andrew Gabriel
    > [email address is not usable -- followup in the newsgroup]


    I completely agree with you, however to debug kernels remotely
    terminal servers / serial port aggregators are used extensively.
    By setting "console=ttya" in the kernel line of grub, you could
    forward kmdb displays to the serial console. This has been tried
    and has worked before.
    I am just wondering why this does not work in my case. Am I missing
    something here ?

    Thanks anyway.
    --Debashis


+ Reply to Thread