PANIC(9) | Kernel Developer's Manual | PANIC(9) |
panic
—
#include <sys/types.h>
#include <sys/systm.h>
void
vpanic
(const
char *fmt, va_list
ap);
void
panic
(const
char *fmt,
...);
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.
panic
() function never returns.
July 14, 2018 | NetBSD 9.0 |