Kernel Panic after Mandy install

[Frank Golden]

I was just browsing at http://www.webservertalk.com/archive99-2010-12-2343588.htmlOne poster suggested that it's not necessary to specify the partition on the initrd line, because it's already specified on the set root line. I haven't tested this, but it's worth a try.Also it appears that Debian runs os-prober and generates a grub.cfg file when running update-grub. I thought this was the case (just from watching the text messages when I install a new kernel), can anyone confirm?

The problem is that os-prober in fact does create that erroneous entry.It's obviously a bug and the grub folks don't give a D*** about it.Maybe it's a bug in os-prober but the GRUB folks chose to implement it in their product and it messes up whendealing with Mandriva and PCLinuxOS and god knows what other linux OS's.I'm very disappointed with the response I got from the GRUB people.They are pushing an inferior product and I suspect they know it. Edited December 26, 2010 by Frank Golden

[sunrat]

The problem is that os-prober in fact does create that erroneous entry.It's obviously a bug and the grub folks don't give a D*** about it.Maybe it's a bug in os-prober but the GRUB folks chose to implement it in their product and it messes up whendealing with Mandriva and PCLinuxOS and god knows what other linux OS's.

That's interesting that it does that in other distros. I just checked my grub.cfg and all the initrd lines do not have the partition specified. All my distros are Debian based - aptosid, Debian Lenny, an older sidux and 64Studio, along with WinXP. All boot fine.One would certainly think either the os-prober devs or the GRUB devs would be interested in fixing it. It seems like a trivial bug.

[Frank Golden]

That's interesting that it does that in other distros. I just checked my grub.cfg and all the initrd lines do not have the partition specified. All my distros are Debian based - aptosid, Debian Lenny, an older sidux and 64Studio, along with WinXP. All boot fine.One would certainly think either the os-prober devs or the GRUB devs would be interested in fixing it. It seems like a trivial bug.

Absolutely right.Most of the distros I have installed are in fact Debian based, the ones that aren't are PCLinusOS 2010 (both kde and Gnome) and Mandriva 2010.2 Gnome all three loosely based on RHL.I've got to assume that other RHL based distros would suffer the same fate with GRUB 2 and os-prober.

[Frank Golden]

Ok, no fix for this GRUB 2 issue but more data.First below is the entry for Mandriva as it appears in Mandriva's /boot/grub/menu.lst, yes Mandy and it's siblings PCLinuxOS KDE and Gnome still use legacy GRUB.

title linuxkernel (hd0,7)/boot/vmlinuz BOOT_IMAGE=linux root=/dev/sda8 resume=/dev/sda6initrd (hd0,7)/boot/initrd.img

As you can see the kernel line and the intrd line contain the (hd0,7) notation and they match in both places.Below is an entry for a Debian based distros /boot/grub/menu.lst in this case Ultimate EDition 2.8.

title Ultimate Edition 2.8root (hd0,9)kernel /boot/vmlinuz-2.6.37-11-generic-pae root=/dev/sda10 resume=/dev/sda6 ro quiet splashinitrd /boot/initrd.img-2.6.37-11-generic-paequiet

As you can see here there is no (hd0,9) notation at the intrd line it's not needed for debian based distros.Now below is the GRUB 2 entry for Mandriva

menuentry "linux (on /dev/sda8)" { insmod part_msdos insmod ext2 set root='(hd0,msdos8)' search --no-floppy --fs-uuid --set f35b3b6e-5afd-4cdf-a453-4022690fecaf linux /boot/vmlinuz BOOT_IMAGE=linux root=/dev/sda8 resume=/dev/sda6 initrd (hd0,7)/boot/initrd.img}

The notation in red is not only not needed but it doesn't match the all important set root lines notation.(hd0,7) is in fact the proper notation for a partition in legacy grub.In legacy grub the numbering system starts with (hdx,0) whereas in GRUB 2 the numbering starts at (hdx,1).So you can see that the set root notation is correct in accordance with the GRUB 2 convention.In GRUB 2 the intrd partition notation isn't even needed, as long as the line shows the path to the initrd.img file everything is ok.The line can read,

initrd /boot/initrd.img

without the partition info and it will boot just fine.I've tested this with Mandy and both PCLinuxOS KDE and Gnome in GRUB 2.The funny thing is that that notation is necessary in legacy GRUB.Without it legacy GRUB produces a grub error 15, file not found error.I've also tested this.The problem as I see it is that os-prober should ignore the partition info at the intrd line but it doesn't.It in fact uses the old convention to number the (hdox,x) notation which is wrong.This is most definitely an issue with both GRUB 2 and os-prober.Since I don't know how nor can find info on how to correct the affected grub.conf file except by manually editing (not recommended by the GRUB 2 folks) the /boot/grub/grub.conf file this is the only fix I know.That is to simply remove the (hdx,x) notation.I can't imagine the distress a bug like this could have on a new linux user.It is a fairly simple fix for an experienced user like myself even though I can't find a proper GRUB 2 method of fixing the entry.Even if there is GRUB 2 approved way (I'm sure there is an obscure, geeky way) to correct this discrepancy the presence of the buggy Debian developed os-prober would simply reproduce the error whenever a kernel upgrade or GRUB 2 upgrade in the host OS was performed.As part of the upgrades the os-prober would be invoked.I can only hope the GRUB 2 folks get their collective head sout of their collective asses and fix this in a later release.They can't be bothered right now however.

Edited December 26, 2010 by Frank Golden