1.\" $NetBSD: panic.9,v 1.14 2002/09/27 15:53:33 wiz Exp $ 2.\" 3.\" Copyright (c) 1996 Michael Graff. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by Michael Graff 17.\" for the NetBSD Project. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31.\" 32.Dd September 27, 2002 33.Dt PANIC 9 34.Os 35.Sh NAME 36.Nm panic 37.Nd Bring down system on fatal error 38.Sh SYNOPSIS 39.Fd #include \*[Lt]sys/types.h\*[Gt] 40.Fd #include \*[Lt]sys/systm.h\*[Gt] 41.Ft void 42.Fn panic "const char *fmt" "..." 43.Sh DESCRIPTION 44The 45.Fn panic 46function terminates the 47.Nx 48system. 49The message 50.Fa fmt 51is a 52.Xr printf 3 53style format string which is printed to the console and saved in the 54variable 55.Va panicstr 56for later retrieval via core dump inspection. 57A newline character is added at the end automatically, and is thus 58not needed in the format string. 59.Pp 60If a kernel debugger is installed, control is passed to it after the 61message is printed. 62If the kernel debugger is 63.Xr ddb 4 , 64control is only passed if the value of the 65.Em ddb.onpanic 66.Xr sysctl 3 67is 68.Dq 1 , 69otherwise, a 70.Xr ddb 4 Ns -specific 71function is used to print the kernel stack trace, and then control returns 72to 73.Fn panic . 74.Pp 75If control remains in 76.Fn panic , 77an attempt is made to save an image of system memory on the 78configured dump device. 79.Pp 80If during the process of handling the panic, 81.Fn panic 82is called again 83.Pq from the filesystem synchronization routines, for example , 84the system is rebooted immediately without synchronizing any filesystems. 85.Sh RETURN VALUES 86The 87.Fn panic 88function does not return. 89.Sh SEE ALSO 90.Xr sysctl 3 , 91.Xr ddb 4 , 92.Xr ipkdb 4 , 93.Xr options 4 , 94.Xr savecore 8 , 95.Xr swapctl 8 , 96.Xr sysctl 8 97