Re: Consistent file system hang with RELENG_6 of today ...

From: Marc G. Fournier (scrappy_at_hub.org)
Date: 07/30/05

  • Next message: Bruce A. Mah: "Re: Quality of FreeBSD" 
    Date: Sat, 30 Jul 2005 00:49:10 -0300 (ADT)
To: Robert Watson <rwatson@FreeBSD.org>

    'k, this is turning out to be alot of fun ... the only machines I have
    here that I can use to talk to the portmaster are Windows boxes ... can
    you recommend a client for windows that would do good logging similar to
    what 'script' does under FreeBSD? :(

    On Fri, 29 Jul 2005, Robert Watson wrote:

    >
    > On Fri, 29 Jul 2005, Marc G. Fournier wrote:
    >
    >> Oh, before I forget ... how do you break to DDB from a serial console? I'll
    >> be running a Portmaster for this ...
    >
    > Compile BREAK_TO_DEBUGGER into the kernel. Then issue a serial break and it
    > should go into the debugger if the low-level console is set to the serial
    > port.
    >
    > On my port-master, I issue a telnet break using "send break" after hitting ^]
    > to generate a serial break for a serial port hooked up to TCP.
    >
    > There's also ALT_BREAK_TO_DEBUGGER, which is documented in NOTES, and
    > provides for an alternative key sequence that doesn't use a break signal.
    >
    > Robert N M Watson
    >
    >>
    >> On Fri, 29 Jul 2005, Robert Watson wrote:
    >>
    >>>
    >>> On Thu, 28 Jul 2005, Marc G. Fournier wrote:
    >>>
    >>>> 'k, I'm starting to play with 6.x, for our new server ... my priority
    >>>> right now is to just have it run the existing 'jail' environments from my
    >>>> 4.x machine, while I work on getting all of our servers up to 6.x, and
    >>>> then will worry about the jail's themselves ...
    >>>>
    >>>> When I try and startup the 4.x jail on my 6.x machine, it "hangs" the
    >>>> file system that the jail directory hierarchy happens to be mounted on
    >>>> though ... twice in a row so far ...
    >>>>
    >>>> Now, I'm suspecting (and am going to try without it) that it might be
    >>>> because I'm mounting devfs within the 4.x jail, but even then, it
    >>>> shouldn't hang things up, only generate a whack of errors ...
    >>>>
    >>>> I have a good dump (CTL-ALT-ESC -> panic), but do not have a clue what to
    >>>> offer from within there that might be of any use ...
    >>>>
    >>>> If anyone is interested ... ?
    >>>
    >>> If you can get into DDB and have serial console output, the following
    >>> would be useful:
    >>>
    >>> The output of 'show pcpu'
    >>>
    >>> The output of 'show pcpu X' for each present cpu, starting with 0.
    >>>
    >>> The output of 'ps'
    >>>
    >>> The output of 'trace' for the currently running thread, and each non-idle
    >>> thread shown in the show pcpu output
    >>>
    >>> The output of 'show lockedvnods'
    >>>
    >>> It would also be useful if, relating to the startup of the jail, you can
    >>> identify the point in the jail boot where it wedges, and if you hit
    >>> Ctrl-T, what process is shown as running and what state it is in, and
    >>> using DDB, trace that process.
    >>>
    >>> If you could show the trace output for each process listed in "show
    >>> lockevnods".
    >>>
    >>> Likely, there is a leaked lock or a low buffer condition. However, once
    >>> we have the above output we should be able to say more. The above will
    >>> hopefully tell us whether it's a vnode deadlock, and ideally, the
    >>> approximate source.
    >>>
    >>> Robert N M Watson
    >>>
    >>>
    >>
    >> ----
    >> Marc G. Fournier Hub.Org Networking Services (http://www.hub.org)
    >> Email: scrappy@hub.org Yahoo!: yscrappy ICQ: 7615664
    >>
    >
    > 

    ----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy@hub.org           Yahoo!: yscrappy              ICQ: 7615664
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