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System Administration Guide: Basic Administration

x86: Forcing a Crash Dump and Reboot of the System

Forcing a crash dump and reboot of the system are sometimes necessary for troubleshooting purposes. The savecore feature is enabled by default.

For more information about system crash dumps, see Chapter 17, Managing System Crash Information (Tasks), in System Administration Guide: Advanced Administration.

Procedurex86: How to Force a Crash Dump and Reboot of the System

If you cannot use the reboot -d or the halt -d command, you can use the kernel debugger, kmdb, to force a crash dump. The kernel debugger must have been loaded, either at boot, or with the mdb -k command, for the following procedure to work.

Note –

You must be in text mode to access the kernel debugger (kmdb). So, first exit any window system.

  1. Access the kernel debugger.

    The method used to access the debugger is dependent upon the type of console that you are using to access the system.

    • If you are using a locally attached keyboard, press F1–A.

    • If you are using a serial console, send a break by using the method appropriate to that type of serial console.

    The kmdb prompt is displayed.

  2. To induce a crash, use the systemdump macro.


    [0]> $<systemdump

    Panic messages are displayed, the crash dump is saved, and the system reboots.

  3. Verify that the system has rebooted by logging in at the console login prompt.

Example 14–6 x86: Forcing a Crash Dump and Reboot of the System by Using halt -d

This example shows how to force a crash dump and reboot of the x86 based system neptune by using the halt -d and boot commands. Use this method to force a crash dump of the system. Reboot the system afterwards manually.


# halt -d
4ay 30 15:35:15 wacked.Central.Sun.COM halt: halted by user

panic[cpu0]/thread=ffffffff83246ec0: forced crash dump initiated at user request

fffffe80006bbd60 genunix:kadmin+4c1 ()
fffffe80006bbec0 genunix:uadmin+93 ()
fffffe80006bbf10 unix:sys_syscall32+101 ()

syncing file systems... done
dumping to /dev/dsk/c1t0d0s1, offset 107675648, content: kernel
NOTICE: adpu320: bus reset
100% done: 38438 pages dumped, compression ratio 4.29, dump succeeded

Welcome to kmdb
Loaded modules: [ audiosup crypto ufs unix krtld s1394 sppp nca uhci lofs 
genunix ip usba specfs nfs md random sctp ]
[0]> 
kmdb: Do you really want to reboot? (y/n) y