How do I make a crash dump using kdb?


At the console type "<return>~k".  This will take you to kdb (kernel debugger)
mode.

        # ~
        DEBUGGER: type ? for help, ^D to quit
        kdb>> 

At the prompt type "sysdump 0 vcall".  This will call the function sysdump
which writes memory to the dump device.

        kdb>> sysdump 0 vcall

        Dumping to dev 01980001 (d_dump=000606E4)
          Memory extent 0 to byte offset 0x1B456000

        gd (ncr0 ID 0, LUN 0) : Resetting controller
          Memory extent 1 to byte offset 0x1D400000

                PCI Sysfault at pc=0x001E6A40:
                       MPC Address Bus Timeout
                       CPU Address = 0x04000000
                       Err Attribute = 0x0000314E

        PANIC: System Fault trap at pc = 0x001E6A40 in supervisor mode.

        DEBUGGER:
                            ^ ERROR: not enough items on stack to pop
        kdb>>

When you see the prompt type "q" to quit.  This will exit kdb and reboot the
system.

        kdb>> q
        DEBUGGER exiting
        CPU 0 halted
        00178fb4 [00178fb4] halt+44        % 7cc00124 mtmsr r6
        CPU 1 halted
        0017fc00 [0017fc00] pause_self+60    48000000 b pause_self+0x60
        dsk(0,0,0,0)/.
        dsk(0,0,0,0)/boot
        PowerMAX OS Boot Loader
        Boot
        : /stand/unix
        2708320+298935+505229 start 0x4000
        symbol table loaded

        Motorola PowerMAX_OS Release 4.2 

        Global Memory: 66756608 bytes

        Initialize I/O level  0 interface: SYS.PCI0
        Initialize I/O level  1 interface: SYS.PCI0.ISA0
        vga0:   on SYS.PCI0.ISA0 
        ...
        File system check complete.

        savecore: System went down at Fri Apr  9 16:23:26 1999
        savecore: Copying /stand/unix to /var/crashfiles/unix.5
        savecore: Saving memory dump to /var/crashfiles/vmcore.5
        savecore: Saved 16384000 bytes of dump to /var/crashfiles/vmcore.5
        ....

During the reboot you should see the savecore messages which indicate the
crashdump succeeded.


For more information see kdb(1), or savecore(1).