NetBSD/share/man/man9/panic.9
jhawk 1fe6e4844f 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.
2000-05-26 20:25:57 +00:00

93 lines
3.0 KiB
Groff

.\" $NetBSD: panic.9,v 1.8 2000/05/26 20:25:57 jhawk 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 May 26, 2000
.Dt PANIC 9
.Os
.Sh NAME
.Nm panic
.Nd Bring down system on fatal error
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <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.
.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 -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
dump device that was configured at the time the kernel was compiled.
.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 sysctl 8