I've just finished compiling 2.6.7 on Slackware 10 but when I reboot I get the following error.

Kernel panic : VFS: Unable to mount root fs on unknown-block(8,3)

My root file system is mounted on an Ext2 partition on sda3. Do I have to edit any files to include 'root=/dev/sda3' as they may be set to hda1? I'm pretty sure I checked the right options in the menuconfig to enable support for Ext2. My compile went smoothly (I followed a number of excellent guides in the forums here) and it starts to boot fine until it gets to the error. I've searched the forums and have found similar posts but they didn't help me. I decided to post here in case it has anything to do with slackware. Please help.

Have you checked the config file for your bootloader?
Have you successfully upgraded a kernel before? (say 2.6.6?)

Simon

Did you run /sbin/lilo as the last step in your compilation?

Also, can you get in your system via a floppy? (I hope you made one )

"Have you checked the config file for your bootloader?"

Do you mean menuconfig? My bootloader is LILO and it seems to be working : ie it dual-boots between windows and Linux properly. Also I've checked the 'lilo.conf' file and it seems to be ok.

"Have you successfully upgraded a kernel before? (say 2.6.6?)"

No. this is my first kernel compile. I was using the 2.4.26 kernel that came with the installation. I did compile the kernel before, but in a seriously reduced capacity. I forgot to check some important fields at the 'make menuconfig' stage.

"Did you run /sbin/lilo as the last step in your compilation?"

No. I ran it now to see if it would work but it didn't. I think I saw the same output it created (Added Windows, added linux etc.) during the main compile though. Would I have to recompile before running /sbin/lilo?

"Also, can you get in your system via a floppy? (I hope you made one )"
Yeah I've made the floppy (I've learned the hard way before) and have since performed a recompile but to no avail.

As it seems that you use scsi hard drive, make sure that you compiled scsi support and scsi driver for your controler as built-in.

What is your output for :

perl -ne 'print if /^([^#]).*(scsi)/i' /usr/src/linux/.config

(assuming you did the symlink /usr/src/linux that point to your 2.6.7 source tree)

I use a SATA hard drive which I believe 2.6.7 supports. I think I saw some files containing the word sata being listed during the compile. I don't use a SCSI drive. I still tried entering the above line but got an error message. However without the square brackets I got the following output.

# SCSI device support
# SCSI support type (disk, tape, CD-ROM)
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
# CONFIG_SCSI_MULTI_LUN is not set
# CONFIG_SCSI_CONSTANTS is not set
# CONFIG_SCSI_LOGGING is not set
# SCSI Transport Attributes
# SCSI low-level drivers
# CONFIG_SCSI_OMIT_FLASHPOINT is not set
# CONFIG_SCSI_EATA_TAGGED_QUEUE is not set
# CONFIG_SCSI_EATA_LINKED_COMMANDS is not set
# CONFIG_SCSI_IZIP_EPP16 is not set
# CONFIG_SCSI_IZIP_SLOW_CTR is not set
# CONFIG_SCSI_SYM53C8XX_IOMAPPED is not set
# CONFIG_SCSI_IPR_TRACE is not set
# CONFIG_SCSI_IPR_DUMP is not set
# CONFIG_SCSI_QLOGIC_FC_FIRMWARE is not set
# PCMCIA SCSI adapter support

Hey that is precisely what I wanted to avoid : all lines beginning by #

The perl command above works for sure, you surelly did a typo, why not just copy & paste it in a terminal ?

Now that we know that you have a sata disk, what is the output for :

cat /usr/src/linux/.config | grep -i sata

Repeater: Cedrik is guiding you down one path - based on some assumptions which may be all to the good. Follw that too, but I have a niggle... this exact thing happened to me during my first kernel ugrade attempt. In my case, the origin was a misidentified root partition as you have suggested in your first post.

Since you are using lilo, it wouldn't hurt to take a sqiz at /boot/lilo.conf to see what it says. You should see an entry for windows, an entry for the 2.6.7 kernel and (hopefully it isn't erased) an entry for the old kernel as well. Compare the old kernel entry to the new one and look what is different - paying especial attention to anything that looks like a root partition ID.

This shouldn't take long.

Cedrik thought you had an scsi hdd because you said the root partition was sda3 and sda would ordinarily denote a scsi hdd, while hda3 would be an ide hdd. (just making sure you two are talking the same language here.)

As a pointer - should you ever recompile, use the option to save the config options to a file and keep it where you can easily find it again (like /root) that way you'll never have to wrack your brains to remember if you've checked that pesky option.

Cheers
Simon

I never checked the option for NTFS support in the menuconfig and my windows (XP) paritition is visible to linux and mounted on /dev/sda1. Could this have been the problem? Anyway my boot disk got corrupted and I had to do a complete reinstall. Doesn't really matter, though, as I've only recently installled Slackware 10. I'll keep this thread open for a while, in case the same thing happens after I compile 2.6.7 now.

I didn't know that SATA devs show up as /dev/sd*. I would expect /dev/hd*.

Can someone colaborate on that?

Hi. Back again. I've been having problems compiling the kernel ever since. I'm attempting to compile 2.6.8.1 now and I'm getting the exact same error as I was in the initial post. To answer earlier questions these are my outputs for the following commands.

perl -ne 'print if /^([^#]).*(scsi)/i' /usr/src/linux/.config

CONFIG_BLK_DEV_IDESCSI=m
CONFIG_SCSI=y
CONFIG_SCSI_PROC_FS=y
CONFIG_SCSI_SPI_ATTRS=m
CONFIG_SCSI_FC_ATTRS=m
CONFIG_SCSI_3W_9XXX=m
CONFIG_SCSI_ACARD=m
CONFIG_SCSI_AACRAID=m
CONFIG_SCSI_AIC7XXX=m
CONFIG_SCSI_AIC79XX=m
CONFIG_SCSI_DPT_I2O=m
CONFIG_SCSI_MEGARAID=m
CONFIG_SCSI_SATA=y
CONFIG_SCSI_SATA_SVW=y
CONFIG_SCSI_ATA_PIIX=y
CONFIG_SCSI_SATA_NV=y
CONFIG_SCSI_SATA_PROMISE=y
CONFIG_SCSI_SATA_SX4=y
CONFIG_SCSI_SATA_SIL=y
CONFIG_SCSI_SATA_SIS=y
CONFIG_SCSI_SATA_VIA=y
CONFIG_SCSI_SATA_VITESSE=y
CONFIG_SCSI_BUSLOGIC=m
CONFIG_SCSI_DMX3191D=m
CONFIG_SCSI_EATA=m
CONFIG_SCSI_EATA_MAX_TAGS=16
CONFIG_SCSI_EATA_PIO=m
CONFIG_SCSI_FUTURE_DOMAIN=m
CONFIG_SCSI_GDTH=m
CONFIG_SCSI_IPS=m
CONFIG_SCSI_INIA100=m
CONFIG_SCSI_PPA=m
CONFIG_SCSI_IMM=m
CONFIG_SCSI_IZIP_EPP16=y
CONFIG_SCSI_SYM53C8XX_2=m
CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=1
CONFIG_SCSI_SYM53C8XX_DEFAULT_TAGS=16
CONFIG_SCSI_SYM53C8XX_MAX_TAGS=64
CONFIG_SCSI_IPR=m
CONFIG_SCSI_QLOGIC_ISP=m
CONFIG_SCSI_QLOGIC_FC=m
CONFIG_SCSI_QLOGIC_1280=m
CONFIG_SCSI_QLA2XXX=y
CONFIG_SCSI_QLA21XX=m
CONFIG_SCSI_QLA22XX=m
CONFIG_SCSI_QLA2300=m
CONFIG_SCSI_QLA2322=m
CONFIG_SCSI_QLA6312=m
CONFIG_SCSI_QLA6322=m
CONFIG_SCSI_DC395x=m
CONFIG_SCSI_DC390T=m
CONFIG_SCSI_NSP32=m
CONFIG_SCSI_DEBUG=m
CONFIG_PCMCIA_NINJA_SCSI=m
CONFIG_I2O_SCSI=m


cat /usr/src/linux/.config | grep -i sata

CONFIG_SCSI_SATA=y
CONFIG_SCSI_SATA_SVW=y
CONFIG_SCSI_SATA_NV=y
CONFIG_SCSI_SATA_PROMISE=y
CONFIG_SCSI_SATA_SX4=y
CONFIG_SCSI_SATA_SIL=y
CONFIG_SCSI_SATA_SIS=y
CONFIG_SCSI_SATA_VIA=y
CONFIG_SCSI_SATA_VITESSE=y

Please help if you can.