I'm afraid there is no easy way I know of. When the kernel boots successfully you can see the logs using dmesg which prints the kernels logging buffer. However, when your kernel panics you can't do this so I was just copying it off the console and reposting it here. One thing I did have to do was in /boot/grub/menu.lst, the entry for my kernel went in with the parameters "quiet" and "splash" which will surpress/hide your kernel logging onto the screen. So just remove them and you will see the logging on the screen. I assume there is an equivalent if you are using LILO.
Thanks,
Stephen
On Wed, Mar 4, 2009 at 4:46 AM, abhimanyu khadtare <linuxthirst030@xxxxxxxxx> wrote:
Congres Stephen,
to get working kernel , i'm totally new to this .If suppose my kernel gets panic how can i captured panic detail to mail here ?On Wed, Mar 4, 2009 at 6:31 AM, Stephen Roberts <sroberts82k@xxxxxxxxxxxxxx> wrote:
Hi guys,
Just to let you know, I got the kernel booted. I did make defconfig but then built the kernel with:
make-kpkg --initrd --append-to-version=-steo kernel_image kernel_headers
Now I'm not sure what the difference is really, I guess this is a sort of all in one tool for building a kernel. The only difference I can see really is the initrd. When I install the resulting deb package I see:
Setting up linux-image-2.6.28-steo (2.6.28-steo-10.00.Custom) ...
Running depmod.
Finding valid ramdisk creators.
Using mkinitramfs-kpkg to build the ramdisk.
Other valid candidates: mkinitramfs-kpkg mkinitrd.yaird
So this tool builds the init ram disk differently.
I have a working kernel now, but I always did and was trying to understand the process. I'd prefer to do it by hand but at least I have a starting point now. I shall update if I can shed any light on it,
Thanks,
StephenOn Tue, Mar 3, 2009 at 12:48 AM, Stephen Roberts <sroberts82k@xxxxxxxxxxxxxx> wrote:
Hi,
The hard disk attatchment is SATA. Looking in /proc/modules on the working version I can see (among many more):
----------------------------------------------------------------
sg 36880 0 - Live 0xf89bc000
sr_mod 17956 0 - Live 0xf88f1000
cdrom 37408 1 sr_mod, Live 0xf8931000
sd_mod 30720 3 - Live 0xf8913000
pata_acpi 8320 0 - Live 0xf889a000
ata_generic 8324 0 - Live 0xf88e6000
ahci 28548 2 - Live 0xf88de000
ata_piix 19588 0 - Live 0xf887c000
libata 159600 4 pata_acpi,ata_generic,ahci,ata_piix, Live 0xf8987000
tg3 116228 0 - Live 0xf8969000
scsi_mod 151436 5 sbp2,sg,sr_mod,sd_mod,libata, Live 0xf8943000
-------------------------------------------------------------------
and doing an lsmod gives me
--------------------------------------------------------------
mbcache 9600 1 ext3
sg 36880 0
sr_mod 17956 0
cdrom 37408 1 sr_mod
sd_mod 30720 3
pata_acpi 8320 0
ata_generic 8324 0
---------------------------------------------------------------
I have enabled anything that looks like it might relate to these. Also, for a change, I tried to use YAIRD to create my initrd as Mulyadi suggested there may be issues with mkinitrd. Also, yaird seems to do a little more analysis to tell me if I am doing stupid things :-)
Doing a 'yaird --test' gives:
yaird error: unsupported device required: sr0 (fatal)
And doing
--------------------------------------------------------------------------------------------------------------------------
stephen@the-batman:/usr/local/src/linux-2.6.28$ sudo yaird -o initrdsteo.img-2.6.28 2.6.28
yaird error: unrecognised device: /sys/devices/platform/i8042/serio0/input
yaird error: unrecognised device: /sys/devices/platform/i8042/serio0/input/input1
yaird error: unrecognised device: /sys/devices/virtual
yaird error: unrecognised device: /sys/devices/virtual/input
yaird error: unrecognised device: /sys/devices/virtual/input/input2
yaird error: unrecognised device: /sys/devices/virtual
yaird error: unrecognised device: /sys/devices/virtual/input
yaird error: unrecognised device: /sys/devices/virtual/input/input4
yaird error: unrecognised device: /sys/devices/LNXSYSTM:00
yaird error: unrecognised device: /sys/devices/LNXSYSTM:00/device:00
yaird error: unrecognised device: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00
yaird error: unrecognised device: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:00
yaird error: unrecognised device: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:00/input
yaird error: unrecognised device: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/LNXVIDEO:00/input/input5
yaird error: there were errors in this run, aborting now without output (fatal)----------------------------------------------------------------------------------------------------------------------------------------
stephen@the-batman:/usr/local/src/linux-2.6.28$
So....yaird is probably telling me I haven't done enough to continue. But I ignored it and went onto use mkinitrd as before with just one warning:Then on boot I saw a lot of SCSI and SATA stuff flash by and then:
FATAL: Module sg not found.
------------------------------------------------------------------------------------------------------------
RAMDISK: Loading into RAM disk... done
List of all partitions:No filesystem could mount root, tried: ext3 vfat msdos iso9660------------------------------------------------------------------------------------------------------------
Kernel Panic - not syncing: VFS: Unable to mount root fs on unkown block(0,0)
Now the last time I tried with just a make defconfig, I got the following partitions listed:The only difference is that I enabled more SATA and SCSI like stuff.
List of all partitions:
0800 sda driver: sd
0801 <numbers> sda1
0802 <numbers> sda2
0803 <numbers> sda3
0804 <numbers> sda4
0b00 <numbers> sr0 driver: sr
Also, I tried make oldconfig using my current kernel config 2.6.24-23-generic (I'm using ubuntu 8.10 distro) but that just gave me the same original devfs problem :(
Sorry for the long mail,
All help much appreciated
StephenOn Mon, Mar 2, 2009 at 2:08 AM, Durga Prasad <writexdp@xxxxxxxxx> wrote:
Hi StephenWhat is your harddisk attachment? SAS? ATA? You need to build the appropriate module for the attachment. (Hint: Check the config for a running kernel)You would need to enable SCSI_LOWLEVEL without which you would not have many low level SCSI drivers.Would enabling EXT2 help?## SCSI Transports#CONFIG_SCSI_SPI_ATTRS=y# CONFIG_SCSI_FC_ATTRS is not setCONFIG_SCSI_ISCSI_ATTRS=y# CONFIG_SCSI_SAS_ATTRS is not set# CONFIG_SCSI_SAS_LIBSAS is not set# CONFIG_SCSI_SRP_ATTRS is not set# CONFIG_SCSI_LOWLEVEL is not set# CONFIG_SCSI_LOWLEVEL_PCMCIA is not set# CONFIG_SCSI_DH is not setRegardsDurga
From: Stephen Roberts <sroberts82k@xxxxxxxxxxxxxx>
To: Durga Prasad <writexdp@xxxxxxxxx>
Cc: Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx>; kernelnewbies@xxxxxxxxxxxx
Sent: Monday, March 2, 2009 2:42:05 AM
Subject: Re: Kernel Panic at boot
Hi Durga,
Attached is my .config file. Let me know if you can see this, thanksOn Sun, Mar 1, 2009 at 8:37 AM, Durga Prasad <writexdp@xxxxxxxxx> wrote:
Hi,Can you provide the .config file used to compile your kernel.- Durga
From: Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx>
To: Stephen Roberts <sroberts82k@xxxxxxxxxxxxxx>
Cc: kernelnewbies@xxxxxxxxxxxx
Sent: Sunday, March 1, 2009 10:42:31 AM
Subject: Re: Kernel Panic at boot--
Hi...
On Sun, Mar 1, 2009 at 6:02 AM, Stephen Roberts
<sroberts82k@xxxxxxxxxxxxxx> wrote:
> Hi,
> Thanks for your response.
>
> I tried what you said and it seemed to help, but when I ran mkinitrd I got
> this:
>
> -------------------------------------------------------------------------------------------------------------------------------------------------
> stephen@the-batman:/usr/local/src/linux-2.6.28$ sudo mkinitrd -o
> initrdsteo.img-2.6.28 2.6.28
> /usr/sbin/mkinitrd: add_modules_dep_2_5: modprobe failed
> FATAL: Module sg not found.
> FATAL: Module sd_mod not found.
> WARNING: This failure MAY indicate that your kernel will not boot!
> but it can also be triggered by needed modules being compiled into
> the kernel.
hmm, i did this to see where sg module should land:
[mulyadi@mulyadi ~]$ cd /lib/modules/`uname -r`
[mulyadi@mulyadi 2.6.27.12-78.2.8.fc9.i686]$ find | grep -i sg
./kernel/drivers/media/video/videobuf-dma-sg.ko
./kernel/drivers/char/ipmi/ipmi_msghandler.ko
./kernel/drivers/scsi/sg.ko
so it seems that sg.ko has something to do with SCSI. are you sure you
have enabled everything related to SCSI? I can't give any hints about
it, so I think other people could help better here.
my other suspicion is, you need to upgrade your mkinitrd to somehow
match the installed kernel version.
> Then when I booted the kernel:
> -------------------------------------------------------------------------------------------------------------------------------------------------
> RAMDISK: Loading into RAM disk... done
> List of all partitions:
> 0800 sda driver: sd
> 0801 <numbers> sda1
> 0802 <numbers> sda2
> 0803 <numbers> sda3
> 0804 <numbers> sda4
> 0b00 <numbers> sr0 driver: sr
> No filesystem could mount root, tried: ext3 vfat msdos iso9660
> Kernel Panic - not syncing: VFS: Unable to mount root fs on unkown
> block(0,0)
Here's my confusion. When I looked the above messages, I think that
you also forgot to compile certain filesystem types. What's the
filesystem type of your root filesystem anyway? and if it's compiled
as kernel modules, are you sure it's included in the initrd image?
regards,
Mulyadi.
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