PANIC(9) BSD Kernel Developer's Manual PANIC(9)NAMEpanic — Bring down system on fatal error
SYNOPSIS
#include <sys/types.h>
#include <sys/systm.h>
void
vpanic(const char *fmt, va_list ap);
void
panic(const char *fmt, ...);
DESCRIPTION
The panic() and vpanic() functions terminate the NetBSD system. The mes‐
sage fmt is a printf(3) style format string which is printed to the con‐
sole and saved in the variable 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.
If a kernel debugger is installed, control is passed to it after the mes‐
sage is printed. If the kernel debugger is ddb(4), control may be passed
to it, depending on the value of ddb.onpanic. See options(4) for more
details on setting ddb.onpanic. If control is not passed through to
ddb(4), a ddb(4)-specific function is used to print the kernel stack
trace, and then control returns to panic().
If control remains in panic(), an attempt is made to save an image of
system memory on the configured dump device.
If during the process of handling the panic, panic() is called again
(from the filesystem synchronization routines, for example), the system
is rebooted immediately without synchronizing any filesystems.
panic() is meant to be used in situations where something unexpected has
happened and it is difficult to recover the system to a stable state, or
in situations where proceeding might make the things worse, leading to
data corruption/loss. It is not meant to be used in scenarios where the
system could easily ignore and/or isolate the condition/subsystem and
proceed.
In general developers should try to reduce the number of panic() calls in
the kernel to improve stability.
RETURN VALUES
The panic() function does not return.
SEE ALSOsysctl(3), ddb(4), ipkdb(4), options(4), savecore(8), swapctl(8),
sysctl(8)BSD September 29, 2011 BSD
