RELENG_5: occasional panic on shutdown

John-Mark Gurney gurney_j at resnet.uoregon.edu
Sat Sep 11 12:35:27 PDT 2004


Thomas-Martin Seck wrote this message on Sat, Sep 11, 2004 at 20:57 +0200:
> Once in a while I drop into ddb when I try to shutdown my RELENG_5
> machine from a serial console; please see below.
> 
> Is there anything interesting I could do in ddb to diagnose the problem?
> 
> $ sudo shutdown -h now
> Shutdown NOW!
> shutdown: [pid 522]
> $
> 
> *** FINAL System shutdown message from thomas at current.tmseck.homedns.org ***
> System going down IMMEDIATELY
> 
> 
> Sep 11 20:50:15 current shutdown: halt by thomas:
> 
> System shutdown time has arrived
> 
> 
> Fatal trap 12: page fault while in kernel mode
> fault virtual address   = 0x1c
> fault code              = supervisor write, page not present
> instruction pointer     = 0x8:0xc04c16cf
> stack pointer           = 0x10:0xcc551784
> frame pointer           = 0x10:0xcc551790
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, def32 1, gran 1
> processor eflags        = interrupt enabled, resume, IOPL = 0
> current process         = 251 (syslogd)
> [thread 100038]
> Stopped at      knote+0x27:     cmpxchgl        %ecx,0x1c(%edx)
> db>

You forgot the back trace on this, do a: tr from the db prompt...
It is also very useful to find out the line number for the address
that it stopped at.. (knote+0x27)...   you can use gdb for this:
gdb kernel.debug
l *knote+0x27

I do have a fix that may fix this, but I can't know if it will until
I get the information above.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."


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