genkernel + initramfs + fbsplash = kernel panic

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

After getting the splash screen to work again with genkernel-3.3.3 (GENSPLASH, not BOOTSPLASH option),
I now get a kernel panic:

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

This is the grub entry that generates the error:

jmbsvicetto · Posted: Sat Jul 30, 2005 2:38 pm Post subject:

Hi.

Have you tried using the following entry?

Henk Poley · n00b Joined: 19 Jul 2004 Posts: 17

Hmm, I'm seeing the same thing. Probably a bug in the initrd :-/

I'll try working around the problem by ignoring the initrd 'root' as per jmbsvicetto's instructions.

Henk Poley · n00b Joined: 19 Jul 2004 Posts: 17

btw, the full error message is (for me):

vincent delft · n00b Joined: 04 Jan 2003 Posts: 58 Location: Belgium

got the same problem here.
But, I can boot without initrd

Compilation was with "genkernel --udev all"

For me this sounds like a problem in the initramfs.

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

vincent delft · n00b Joined: 04 Jan 2003 Posts: 58 Location: Belgium

I'm using the Portage of 2005/07/29.
And by emerging genkernel (stable) I've got 3.3.3.

Indeed, --udev is no more needed, but that's no the cause of the Kernel Panic.

I'm just restarting the whole installation process by looking carefuly at each steps ... we will see.

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

I'm just going through the output of genkernel again to make sure I understand exactly what it's asking for (it's not the first time previously working parameters stop working after a genkernel update.)

Here's what it says for me:

vincent delft · n00b Joined: 04 Jan 2003 Posts: 58 Location: Belgium

still the same :cry:

Now, I'm sure, I've followed each setps as described on the installation guide.

I'm using genkernel 3.3.3, linux 2.6.12-gentoo-r6, I've used the portage of 20050729 (last one).

my grub.conf is:

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

I've reported the bug to Gentoo bugzilla as bug #100846 https://bugs.gentoo.org/show_bug.cgi?id=100846
I've included this thread as a reference.

vincent delft · n00b Joined: 04 Jan 2003 Posts: 58 Location: Belgium

I've added "vga=791 splash=silent" like requested in the genkernel.log file.

But, this has no impact. Kernal panic at the same place.

Henk Poley · n00b Joined: 19 Jul 2004 Posts: 17

According to the bugreport the following should fix it:

# emerge --sync
# emerge genkernel

be sure to get genkernel > 3.3.4, and not 3.3.3

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

I'm happy that it's apparently fixed (haven't tried it yet), but it still bothers me that genkernel-3.3.3 was marked stable with this bug present.
I live in the unstable tree so I expect the odd glitch, but stable tree users shouldn't be test guinea pigs; for them it's the quality, not the quantity, of the updates that count. With genkernel updates occurring on an almost daily basis, it doesn't sound anywhere near stable yet.

genkernel-3.2.9 has been out for about a week, so if there are no known issues with it that's probably the version that belongs in the stable tree.
Failing that, 3.1.6 is a fairly safe bet.

depontius · Advocate Joined: 05 May 2004 Posts: 3509

This doesn't appear to be a problem with just fbsplash. It appears to be a problem simply using initramfs.

Perhaps I don't have all the right kernel switches set, but I'm not using fbsplash, and get the same boot symptoms as the rest of you when I try to use initramfs. I'm now booting without initrd, just fine. I'm just glad I didn't really need an initrd to boot.

From what I can tell off of the kernel list, initramfs is the start of some really major boot changes, not the least of which is deprecation of non-modular kernels - all "*" that can be "M" will be "M", and the "*" will go away. The initramfs was slipped into Gentoo, almost by stealth, with 2.6.12. It has given me trouble of some form, every time I've tried to use it. I guess it's a good thing the bugs are getting hammered out now, before it becomes absolutely necesssary.

Now I've got to get my server off of devfs and onto udev, since they've deprecated it with teeth in the new kernel. Fortunately all of my other systems are udev.
_________________
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automan · n00b Joined: 02 May 2005 Posts: 19

ozbird · Apprentice Joined: 21 Oct 2003 Posts: 185

AusGen · Posted: Sun Jul 31, 2005 7:02 am Post subject: Still bugged as of 31 Jun 05

Thanks for all the above advice, removing the initrd line, and associated flags in the kernel, (root=/dev/ram0 real_root= etc...) fixes the bootup problem. I also followed the advice to emerge --sync and update genkernel to 3.3.5, but this has not fixed the problem. It appears the initramfs (initrd) is still bugged. The genkernel command I was using was :
genkernel --mrproper --lvm2 --install --bootsplash --kernname=ati_alsa --menuconfig all
(lvm2 as I have /usr /var and /home on lvm2)

Noob question: Why bother with initrd if it boots without it?

This is my first post, I've just changed over to Gentoo from Debian for my AMD64. With the exception of the above problem I've been impressed with what I've seen so far. Distcc rocks with Gentoo!

vincent delft · n00b Joined: 04 Jan 2003 Posts: 58 Location: Belgium

In my case an emerge sync has solve the problem.

To sum up, I've done:
- emerge sync
- emerge genkernel (which give me 3.3.5)
- genkernel all
- grub-install /dev/hda
- reboot.

jaybode · n00b Joined: 31 Jul 2005 Posts: 3

Great stuff everyone..
My first crack at Gentoo and I am mighty impressed with portage and the use support.

Just a note, the Aust. mirror is still behind in revisions. The US site sync'ed to ver. 3.3.5
Remerging Genkernal now..
:roll:

Cheers,

depontius · Advocate Joined: 05 May 2004 Posts: 3509

jaybode · n00b Joined: 31 Jul 2005 Posts: 3

Using 3.5.5 works the trest.. cheers everyone..

Ausgen - Initrd is used mainly because of using genkernel.. this gentoo-kernel is like the Bootable CD one, in that it detects hardware etc. then boots the real kernel with all the modules it found that it needed duing the 'mini boot' from Ram disk (using Initrd)

I am probably wrong, but this is how I saw it (anyone correct me if Im wrong)

I started with building my own Kerenel, but like the idea of GenKernel so if I move my system to USB portable laptop drive.
I can then boot of 'most' computers (BIOS capable, or a floppy/CD to kick it off).

The emerge build for genkernel was stuffed - I followed the instructions. I think the ramfs-image was not loading the right kernel support for the ramdisk. These are the sort of messages (the very first one anyway) that you get when you have not compiled the correct filesystem support into the kernel that your trying to boot from.

Not bad hey, 2 weeks into Linux and I already sound like a geek.

Cheers,

J

depontius · Advocate Joined: 05 May 2004 Posts: 3509

Jabode, you're close, but there are a few details that are off.

There are 2 ways to build a kernel, monolithic and modular. With a monolithic kernel, all of the drivers and filesystems, etc are compiled into the kernel. With a modular kernel, drivers, filesystems, etc are compiled separately, and loaded at run time. The problem with modules is that you need disk and filesystem access in order to get them. That means if your chipset disk or filesystem driver, etc is in a module, you can't get there in order to load the modules.

Enter the initrd. It's a ramdisk that's loaded with a disk image that contains the necessary drivers. You don't even really need *all* of the drivers, just enough to get disk (or network, for networked filesystems) access, in order to get at the rest of the modules. You're still using the same kernel, just loading things from a different source. Incidentally, there's an operation called pivot_root that switches you from the initrd to the real disk, once you're ready.

Why modular kernel? Because every driver makes the kernel bigger. In the old days, maybe even now, there was a maximum size, and modules were a way to get around that. Even without the maximum size, those extra drivers would just waste memory. With modules, it's possible to come up with a one-size-fits-almost-all kernel, wasting only disk space (cheap) for the modules themselves.

Why the change to initramfs? Right now, each driver needs two methods of initialization, monolithic and modular. The kernel guys would like to simplify things, and only have the one initialization method - modular. At the same time, they recognized that the initrd is a rather limited startup mechanism. So they're working toward an improvement - "early userspace," essentially like initrd, only more versatile. Once initramfs and early userspace are all in place and well bugged out, they're going to yank the monolithic initialization code. (in a few years) Drivers will get simpler, hopefully more reliable. But we'll all have to get used to using an initramfs.
_________________
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c0p · n00b Joined: 29 Jul 2005 Posts: 56

how do i emerge an old genkernel version? i want to stick with gentoo but it doesn't seem to be working for me in 2.6-12-r6. It doesn't get my eth0 or mouse so far...haven't been able to go much further without the network reliant emerges