Hey All:

I decided to compile a 2.6.0 kernel for my new Slackware laptop. You've gotta learn sometime, right? So after a bit of researching, I went through all of the motions, rebooted, and now I'm faced with:

VFS: Cannot open root device "305" or hda5
Please append a correct "root=" boot option
Kernel panic: VFS: Unable to mount root fs

I had absolutely no error messages at any other point in the process of compiling the new kernel, and I thought everything was going very smoothly (new support for ACPI and Centrino stuff in 2.6 makes me happy). I succesfully compiled the kernel, installed the modules, edited Lilo, relinked System.map, etc.

Can anybody help me troubleshoot this? My primary Linux partition is, indeed, on hda5, and the hard drive itself is a Toshiba IDE 60 GB. The Slackware stock 2.4 kernel works perfectly fine.

Thanks,

rk

If the root is on hda5, then you must tell grub hda4. Grub's counting starts at 0, so if you root is on the 1st partition of your 1st hard drive (hda1) then you would enter into Grub root=(hd0,0).

rberry88

Thanks for the response, but I'm actually using lilo and not grub. The relevant pieces of my lilo.conf:

image = /boot/vmlinuz
root = /dev/hda5
label = Slackware
read-only

image = /boot/vmlinuz-2.6.0
root = /dev/hda5
label = 2.6.0
read-only

The "Slackware" one, which is 2.4.22, works fine. The "2.6.0" one is the one I'm having problems with...

Thanks in advance.

Edit: The kernel itself begins booting fine. Many things are loaded before the error messages occurs. It's as though it hangs when it's about to start up all of the services (well, when it needs to access the filesystem).

Then I would say that the Kernel Panic is more relevant to not having the correct filesystems compiled into the kernel. I would make sure you have devfs, reiserfs, ext2 and ext3 just to avoid trouble. If you already have this then maybe someone else can jump in here and try to shed more light on this.

rberry88

I compiled in support for ext2 and ext3, but not devfs (the 2.6 menuconfig claims devfs is obsolete), and not reiserfs (I only have one Linux partition - ext3, hda5, and one swap partition). I can certainly recompile with devfs and reiserfs, but will that make a difference?

rk

I think it appears to be what your problem is. I would compile them both in and see if the problem persists, if not then problem solved. If the problem remains after trying this then we've eliminated one area of troubleshooting.

rberry88

Check your Device Drivers -> ATA/ATAPI/MFM/RLL Support

Make sure that your IDE chipset support is compiled into the kernel.

What options am I looking for, specifically, in the menuconfig? I suppose it's possible I missed it the first time around (although one would assume the kernel defaults to compiling IDE support int).

I found the following upon grep'ing IDE in my .config:

CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y
# CONFIG_BLK_DEV_HD_IDE is not set
CONFIG_BLK_DEV_IDEDISK=y
# CONFIG_IDE_CHIPSETS is not set

ATA/ATAPI/MFM/RLL support is selected, as is Enhanced IDE/MFM... support.

Am I missing something obvious?

rk

I would set these two items to 'yes' (compile in) since you are, most likely, using an IDE hard drive and your motherboard supports and IDE chipset.

You can always select the "help" selection while in menuconfig and it will tell you what exactly it enables and it will give you an idea if it is relevant to your setup.

rberry88

I agree, rberry, but I can't find the relevant entries in menuconfig. I checked off everything I thought was needed for my IDE hard drive while in menuconfig, yet those still ended up 'not set'. This being my first kernel upgrade, I did go through and get help for every entry I was unsure of. Ack, so frustrated.

rk

Edit: Also, Intel PIIXn chipset support is enabled. That is what my i855 mobo uses, right? Or am I making that up?

I would look in "Filesystems" "Devices --" to start with. Sorry, I don't have a linux box here at work so I can't actually check until I get home. Just start at the top and go through each one to make sure. I know it can get tiresome and boring but it will be well worth it in the end when all is working how you want it to and you know you did it.

rberry88

rberry:

Later tonight I'll recompile a 2.6.0 kernel, taking special care re: IDE devices, and enabling support for all major file systems (not just ext3 and ext2). I'll let you know what the results are. If you end up figuring out what CONFIG_BLK_DEV_HD_IDE and CONFIG_IDE_CHIPSETS are linked to in menuconfig, let me know.

Thanks,

rk

Okay, I just compiled kernel 2.6.1 in Arch Linux with no problems and I did find the section you are looking for under "Filesystems" and "Devices". Whenever you see this "---->" after an entry in the menuconfig screen make sure you hit enter so it takes you to the submenu for that item. Under the Filesystems category in menuconfig there are a few submenus that I had to navigate to find the UFS and XFS filesystem options. The UFS and/or XFS selections say "deprecated" or "obsolete" next to them but you can still mark them (*) to compile which is what you want to do.

The other items for the IDE HD and CHIPSETS are under the "Device Drivers" menu in menuconfig.

rberry88

rberry:

Okie doke, I'm about to compile with UFS and XFS. This begs the questions, however, why the devil do I need them? Their descriptions lead me to believe they have absolutely nothing to do with my system. (The XFS description begins with 'blah blah blah originated on the SGI IRIX platform' and UFS begins 'BSD and derivate versions of Unix') Just seems odd.

I'm gonna go read up on video card stuff (something about compiling with framebuffer support as normal VESA to avoid problems in 2.6), but after I compile and reboot, I'll post my results.

Thanks,

rk

And the results are:

BLANK SCREEN (after lilo)

What the hell? As far as I know, I essentially recompiled the exact same kernel as before, except this time adding support for XFS and UFS. And yet, now it won't even boot the kernel.

Life is tough.

EDIT: Turns out it was a framebuffer thing. I had framebuffer support enabled using Radeon, but when I set it to normal VESA, it booted fine. *shrug*

At any rate, the system boots properly now. No error messages, aside from some OSS stuff. I have yet to test out the speed of 2.6 compared to 2.4.22, but hopefully this will be worth it. Thanks for your help, rberry!