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| -rw-r--r-- | share/man/man8/Makefile | 4 | ||||
| -rw-r--r-- | share/man/man8/crash.8 | 144 |
2 files changed, 146 insertions, 2 deletions
diff --git a/share/man/man8/Makefile b/share/man/man8/Makefile index 1e5d769db1a..55748ae5bb8 100644 --- a/share/man/man8/Makefile +++ b/share/man/man8/Makefile @@ -1,10 +1,10 @@ -# $OpenBSD: Makefile,v 1.23 1999/07/20 18:35:35 aaron Exp $ +# $OpenBSD: Makefile,v 1.24 2000/02/28 22:36:42 deraadt Exp $ # $NetBSD: Makefile,v 1.13 1996/03/28 21:36:40 mark Exp $ # @(#)Makefile 8.1 (Berkeley) 6/5/93 MAN= afterboot.8 compat_bsdos.8 compat_freebsd.8 compat_ibcs2.8 \ compat_linux.8 compat_sunos.8 \ - compat_svr4.8 compat_ultrix.8 dhcp.8 diskless.8 intro.8 rc.8 \ + compat_svr4.8 compat_ultrix.8 crash.8 dhcp.8 diskless.8 intro.8 rc.8 \ rc.conf.8 rc.shutdown.8 ssl.8 sticky.8 update.8 yp.8 boot_config.8 \ vpn.8 SUBDIR= man8.amiga man8.arm32 man8.atari man8.hp300 man8.i386 man8.mac68k \ diff --git a/share/man/man8/crash.8 b/share/man/man8/crash.8 new file mode 100644 index 00000000000..e1b98b02a50 --- /dev/null +++ b/share/man/man8/crash.8 @@ -0,0 +1,144 @@ +.\" Copyright (c) 1980, 1991 The Regents of the University of California. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" from: @(#)crash.8 6.5 (Berkeley) 4/20/91 +.\" $Id: crash.8,v 1.1 2000/02/28 22:36:42 deraadt Exp $ +.\" +.Dd February 23, 2000 +.Dt crash 8 +.Os +.Sh NAME +.Nm crash +.Nd system failure and diagnosis +.Sh DESCRIPTION +This section explains what happens when the system crashes +and (very briefly) how to analyze crash dumps. +.Pp +When the system crashes voluntarily it prints a message of the form +.Pp +.Bd -literal + panic: why i gave up the ghost +.Ed +.Pp +on the console, and enters the kernel debugger +.Xr ddb 4 +if it is compiled into the kernel. +If +.Xr ddb 4 +is not in the kernel, the system takes a dump on a mass storage +peripheral, and then invokes an automatic reboot procedure as +described in +.Xr reboot 8 . +(If auto-reboot is disabled (in a machine dependent way) the system +will simply halt at this point.) +Unless some unexpected inconsistency is encountered in the state +of the file systems due to hardware or software failure, the system +will then resume multi-user operations. +.Pp +The system has a large number of internal consistency checks; if one +of these fails, then it will panic with a very short message indicating +which one failed. +In many instances, this will be the name of the routine which detected +the error, or a two-word description of the inconsistency. +A full understanding of most panic messages requires perusal of the +source code for the system. +.Pp +The most common cause of system failures is hardware failure, which +can reflect itself in different ways. Here are the messages which +are most likely, with some hints as to causes. +Left unstated in all cases is the possibility that hardware or software +error produced the message in some unexpected way. +.Bl -tag -width indent +.It no init +This panic message indicates filesystem problems, and reboots are likely +to be futile. Late in the bootstrap procedure, the system was unable to +locate and execute the initialization process, +.Xr init 8 . +The root filesystem is incorrect or has been corrupted, or the mode +or type of /sbin/init forbids execution. +.It timeout table overflow +.ns +This really shouldn't be a panic, but until the data structure +involved is made to be extensible, running out of entries causes a crash. +If this happens, make the timeout table bigger. +.It trap type %d, code=%x, pc=%x +A unexpected trap has occurred within the system; the trap types are +machine dependent and can be found listed in +.Pa /sys/arch/ARCH/include/trap.h . +.Pp +The code is the referenced address, and the pc at the +time of the fault is printed. These problems tend to be easy to track +down if they are kernel bugs since the processor stops cold, but random +flakiness seems to cause this sometimes. +The kernel debugger +.Xr ddb 4 +can be used to locate the instruction and subroutine corresponding +to the PC value. +If that is insufficient to suggest the nature of the problem, +more detailed examination of the system status at the time of the trap +usually can produce an explanation. +.It init died +The system initialization process has exited. This is bad news, as no new +users will then be able to log in. Rebooting is the only fix, so the +system just does it right away. +.It out of mbufs: map full +The network has exhausted its private page map for network buffers. +This usually indicates that buffers are being lost, and rather than +allow the system to slowly degrade, it reboots immediately. +The map may be made larger if necessary. +.El +.Pp +That completes the list of panic types you are likely to see. +.Pp +When the system crashes it writes (or at least attempts to write) +an image of memory into the back end of the dump device, +usually the same as the primary swap +area. After the system is rebooted, the program +.Xr savecore 8 +runs and preserves a copy of this core image and the current +system in a specified directory for later perusal. See +.Xr savecore 8 +for details. +.Pp +To analyze a dump you should begin by running +.Xr gdb 1 . +Once gdb starts, use the command +.Pp +.Bd -literal + target kcore /dev/mem +.Ed +NIKLAS NIKLAS. +.Pp +Then a traceback and other such things can be gotten. +.Sh "SEE ALSO" +.Xr gdb 1 , +.Xr ddb 4 , +.Xr reboot 8 |