| PANIC(9) | Kernel Developer's Manual | PANIC(9) |
panic — bring down
system on fatal error
#include
<sys/types.h>
#include <sys/systm.h>
void
vpanic(const
char *fmt, va_list
ap);
void
panic(const
char *fmt,
...);
The
panic()
and
vpanic()
functions terminate the NetBSD system. The message
fmt is a
printf(3) style format string
which is printed to the console 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 message 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 things worse, leading to data
corruption and/or 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.
The panic() function never returns.
printf(3), sysctl(3), ddb(4), options(4), savecore(8), swapctl(8), sysctl(8), printf(9)
| October 4, 2019 | NetBSD 11.0 |