| Infodoc ID |
|
Synopsis |
|
Date |
| 11834 |
|
What is a watchdog reset? |
|
2 Jun 1998 |
What is a watchdog reset?
A watchdog reset is an unrecoverable situation that forces the CPU
to reset. It is caused as a result of the machine trapping while
handling a trap with the "Enable Traps" bit in the Processor Status
Register (PSR) being disabled. The reason traps have been disabled
is that no other traps should occur unit the first trap has been
handled. But because a second trap has occurred and the cpu cannot
handle it the machine resets.
Typically this indicates a software problem, but may be hardware
related.
What to do?:
If the machine dropped to the boot PROM ok prompt there are a few
special PROM command you can run to gather information.
.registers - Displays kernel internal registers.
.locals - Displays the registers in the current register
window.
.psr - Displays the Processor Status Register.
ctrace - Displays the trace of the current thread.
The data is output in all hex. If your
system is running Solaris 2.5 or newer
put this line in /etc/system for symbol
names instead of hex.
set obpsym = 1
Sun4d's Only:
On sun4d systems if the machine automatically rebooted after a
system watchdog reset, you can run the command /usr/kvm/prtdiag
to gather the information that wassaved to the NVRAM once the
machine has finished its reboot.
If the machine dropped to the boot PROM ok prompt you can run
wd-dump command at the prompt. This displays the watchdog information
on the screen including the address of the instruction that caused
the reset.
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