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Allow dump device be configured as early as possible using loader(8) tunable.

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This allows obtaining crash dumps from the panics occured during late stages
of kernel initialisation before system enters into single-user mode.

MFC after:	2 weeks
This commit is contained in:
Maxim Sobolev 2002-01-21 01:16:11 +00:00
parent 01b8b9e983
commit dcd7d9b7b7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=89601
4 changed files with 30 additions and 6 deletions
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18
sbin/dumpon/dumpon.8
View File

@ -93,12 +93,24 @@ or to
.Ar special_file
is the text string:
.Dq Li off .
.Pp
Since
.Nm
can only be called after the system enters single-user mode,
it can not be used to create dumps
for system panics during kernel initialization. In such cases you
have to use
.Va dumpdev
tunable provided by
.Xr loader 8
instead.
.Sh SEE ALSO
.Xr sysctl 3 ,
.Xr fstab 5 ,
.Xr rc.conf 5 ,
.Xr config 8 ,
.Xr init 8 ,
.Xr loader 8 ,
.Xr rc 8 ,
.Xr savecore 8 ,
.Xr swapon 8 ,
@ -113,12 +125,6 @@ boot-time system configuration
.Sh BUGS
Because the filesystem layer is already dead by the time a crash dump
is taken, it is not possible to send crash dumps directly to a file.
.Pp
Since
.Nm
can only be called after the system enters single-user mode,
it can not be used to create dumps
for system panics during kernel initialization.
.Sh HISTORY
The
.Nm

6
sys/boot/common/loader.8
View File

@ -392,6 +392,12 @@ when the kernel is booted.
This can be overridden by setting
.Va rootdev
explicitly.
.It Va dumpdev
A name of device where the kernel can save a crash dump in the case
of a panic. This automatically sets
.Va kern.dumpdev
.Xr sysctl 3
MIB variable.
.El
.Pp
Other variables are used to override kernel tunable parameters.

1
sys/boot/forth/loader.conf
View File

@ -64,6 +64,7 @@ module_path="/boot/kernel;/boot/modules;/modules" # Set the module search path
#boot_verbose="NO" # Causes extra debugging information to be printed
#init_path="/sbin/init:/sbin/oinit:/sbin/init.bak:/stand/sysinstall"
# Sets the list of init candidates
#dumpdev="ad0s1b" # Set device for crash dumps
##############################################################

11
sys/kern/kern_shutdown.c
View File

@ -54,6 +54,7 @@
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/reboot.h>
@ -457,6 +458,16 @@ setdumpdev(dev_t dev)
static void
dump_conf(void *dummy)
{
char *path;
dev_t dev;
path = malloc(MNAMELEN, M_TEMP, M_WAITOK);
if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
dev = getdiskbyname(path);
if (dev != NODEV)
dumpdev = dev;
}
free(path, M_TEMP);
if (setdumpdev(dumpdev) != 0)
dumpdev = NODEV;
}