NetBSD/share/man/man9/panic.9

.\"     $NetBSD: panic.9,v 1.15 2003/04/16 13:35:31 wiz Exp $
.\"
.\" Copyright (c) 1996 Michael Graff.
.\" 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 Michael Graff
.\"      for the NetBSD Project.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
.\"
.Dd September 27, 2002
.Dt PANIC 9
.Os
.Sh NAME
.Nm panic
.Nd Bring down system on fatal error
.Sh SYNOPSIS
.In sys/types.h
.In sys/systm.h
.Ft void
.Fn panic "const char *fmt" "..."
.Sh DESCRIPTION
The
.Fn panic
function terminates the
.Nx
system.
The message
.Fa fmt
is a
.Xr printf 3
style format string which is printed to the console and saved in the
variable
.Va panicstr
for later retrieval via core dump inspection.
A newline character is added at the end automatically, and is thus
not needed in the format string.
.Pp
If a kernel debugger is installed, control is passed to it after the
message is printed.
If the kernel debugger is
.Xr ddb 4 ,
control is only passed if the value of the
.Em ddb.onpanic
.Xr sysctl 3
is
.Dq 1 ,
otherwise, a
.Xr ddb 4 Ns -specific
function is used to print the kernel stack trace, and then control returns
to
.Fn panic .
.Pp
If control remains in
.Fn panic ,
an attempt is made to save an image of system memory on the
configured dump device.
.Pp
If during the process of handling the panic,
.Fn panic
is called again
.Pq from the filesystem synchronization routines, for example ,
the system is rebooted immediately without synchronizing any filesystems.
.Sh RETURN VALUES
The
.Fn panic
function does not return.
.Sh SEE ALSO
.Xr sysctl 3 ,
.Xr ddb 4 ,
.Xr ipkdb 4 ,
.Xr options 4 ,
.Xr savecore 8 ,
.Xr swapctl 8 ,
.Xr sysctl 8
Use .In header.h instead of .Fd #include \[Lt]header.h\[Gt] Much easier to read and write, and supported by groff for ages. Okayed by ross. 2003-04-16 17:34:34 +04:00			`.\" $NetBSD: panic.9,v 1.15 2003/04/16 13:35:31 wiz Exp $`
add copyright and netbsd rcs tag 1996-10-09 21:20:04 +04:00			`.\"`
			`.\" Copyright (c) 1996 Michael Graff.`
			`.\" 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 Michael Graff`
			`.\" for the NetBSD Project.`
Fix formatting errors (bad sentence breaks). 1999-03-07 01:09:29 +03:00			`.\" 4. The name of the author may not be used to endorse or promote products`
add copyright and netbsd rcs tag 1996-10-09 21:20:04 +04:00			`.\" derived from this software without specific prior written permission`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.`
			`.\"`
Add a line saying that a trailing '\n' is not needed. Bump date. While here: new sentence, new line. 2002-09-27 19:53:33 +04:00			`.Dd September 27, 2002`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Dt PANIC 9`
			`.Os`
			`.Sh NAME`
			`.Nm panic`
			`.Nd Bring down system on fatal error`
			`.Sh SYNOPSIS`
Use .In header.h instead of .Fd #include \[Lt]header.h\[Gt] Much easier to read and write, and supported by groff for ages. Okayed by ross. 2003-04-16 17:34:34 +04:00			`.In sys/types.h`
			`.In sys/systm.h`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Ft void`
Fix .Fn arguments. 2002-08-06 17:02:52 +04:00			`.Fn panic "const char *fmt" "..."`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Sh DESCRIPTION`
			`The`
			`.Fn panic`
macroize BSD, NetBSD, FreeBSD and misc cleanup 1998-02-06 08:54:12 +03:00			`function terminates the`
			`.Nx`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`system.`
			`The message`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Fa fmt`
			`is a`
			`.Xr printf 3`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`style format string which is printed to the console and saved in the`
			`variable`
Boring whitespace fixes. 2001-09-04 06:51:15 +04:00			`.Va panicstr`
If db_onpanic is unset and DDB is compiled in, panic() now calls db_stack_trace_print(__builtin_frame_address(0),...), to printf() the stack trace to the message bufffer and console. Idea from SunOS/Solaris. Useful when dumping fails. 2000-05-27 00:25:57 +04:00			`for later retrieval via core dump inspection.`
Add a line saying that a trailing '\n' is not needed. Bump date. While here: new sentence, new line. 2002-09-27 19:53:33 +04:00			`A newline character is added at the end automatically, and is thus`
			`not needed in the format string.`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Pp`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`If a kernel debugger is installed, control is passed to it after the`
Add a line saying that a trailing '\n' is not needed. Bump date. While here: new sentence, new line. 2002-09-27 19:53:33 +04:00			`message is printed.`
			`If the kernel debugger is`
If db_onpanic is unset and DDB is compiled in, panic() now calls db_stack_trace_print(__builtin_frame_address(0),...), to printf() the stack trace to the message bufffer and console. Idea from SunOS/Solaris. Useful when dumping fails. 2000-05-27 00:25:57 +04:00			`.Xr ddb 4 ,`
			`control is only passed if the value of the`
			`.Em ddb.onpanic`
			`.Xr sysctl 3`
			`is`
			`.Dq 1 ,`
			`otherwise, a`
Add a line saying that a trailing '\n' is not needed. Bump date. While here: new sentence, new line. 2002-09-27 19:53:33 +04:00			`.Xr ddb 4 Ns -specific`
If db_onpanic is unset and DDB is compiled in, panic() now calls db_stack_trace_print(__builtin_frame_address(0),...), to printf() the stack trace to the message bufffer and console. Idea from SunOS/Solaris. Useful when dumping fails. 2000-05-27 00:25:57 +04:00			`function is used to print the kernel stack trace, and then control returns`
			`to`
			`.Fn panic .`
			`.Pp`
			`If control remains in`
			`.Fn panic ,`
			`an attempt is made to save an image of system memory on the`
the dump device isn't hardcoded into compiled kernel commonly nowadays xref swapctl(8) 2001-12-04 22:56:55 +03:00			`configured dump device.`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Pp`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`If during the process of handling the panic,`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Fn panic`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`is called again`
Add a line saying that a trailing '\n' is not needed. Bump date. While here: new sentence, new line. 2002-09-27 19:53:33 +04:00			`.Pq from the filesystem synchronization routines, for example ,`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`the system is rebooted immediately without synchronizing any filesystems.`
add panic(9) man page 1996-08-11 03:14:11 +04:00			`.Sh RETURN VALUES`
			`The`
			`.Fn panic`
			`function does not return.`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`.Sh SEE ALSO`
If db_onpanic is unset and DDB is compiled in, panic() now calls db_stack_trace_print(__builtin_frame_address(0),...), to printf() the stack trace to the message bufffer and console. Idea from SunOS/Solaris. Useful when dumping fails. 2000-05-27 00:25:57 +04:00			`.Xr sysctl 3 ,`
			`.Xr ddb 4 ,`
			`.Xr ipkdb 4 ,`
Cleaned up some statements. Added cross references to related pages. 1998-09-03 05:05:03 +04:00			`.Xr options 4 ,`
If db_onpanic is unset and DDB is compiled in, panic() now calls db_stack_trace_print(__builtin_frame_address(0),...), to printf() the stack trace to the message bufffer and console. Idea from SunOS/Solaris. Useful when dumping fails. 2000-05-27 00:25:57 +04:00			`.Xr savecore 8 ,`
Sort SEE ALSO. 2001-12-05 02:16:15 +03:00			`.Xr swapctl 8 ,`
			`.Xr sysctl 8`