370c3cb57c
This commit has two pieces. One half is the watchdog kernel code which lives primarily in hardclock() in sys/kern/kern_clock.c. The other half is a userland daemon which, when run, will keep the watchdog from firing while the userland is intact and functioning. Approved by: jeff (mentor)
78 lines
2.3 KiB
Groff
78 lines
2.3 KiB
Groff
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.\" Copyright (c) 2003 Sean M. Kelly <smkelly@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd June 25, 2003
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.Dt WATCHDOG 4
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.Os
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.Sh NAME
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.Nm watchdog
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.Nd Software watchdog
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.Sh SYNOPSIS
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.Cd options WATCHDOG
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.Sh DESCRIPTION
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.Nm
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is a set of checks and routines which allow the implementation of a software
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watchdog solution.
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.Pp
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The user interface for
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.Nm
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is implemented via a trio of sysctl OIDs.
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When
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.Li debug.watchdog.enabled
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is set to a positive value,
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.Nm
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timeout checks are performed.
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In order to keep the watchdog from triggering,
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.Li debug.watchdog.reset
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must be accessed,
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by reading or writing,
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within every
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.Li debug.watchdog.timeout
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seconds.
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Failure to keep the
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.Nm
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updated will result in the kernel outputting interrupt counts,
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backtraces,
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and then attempting to enter
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.Xr ddb 9 .
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.Sh SEE ALSO
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.Xr sysctl 8 ,
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.Xr watchdogd 8
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.Sh HISTORY
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The
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.Nm
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code first appeared in
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.Fx 5.1 .
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.Sh AUTHORS
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.An -nosplit
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The
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.Nm
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code and manual page were written by
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.An Sean Kelly Aq smkelly@FreeBSD.org .
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Some contributions were made by
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.An Jeff Roberson Aq jeff@FreeBSD.org .
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