prelink broke my system [again!]

Massimo B. · Last edited by Massimo B. on Sat Dec 16, 2006 10:30 am; edited 3 times in total

The last thing I did was prelink -Ramvq as usual. There were a lot of messages like "could not prelink because of ..dependency" which was curious enough. After that no command was possible anymore, no ls or ps, I just got "Semgentation fault".
After restart I get a kernel panic right at the beginning, something like "init 11, no handler specified".
A chroot from the universal-cd also gives "segmantation fault". init seems to be broken.

Now the only way is to copy a stage3 over and emerge -e world.

The gentoo.de prelink guide sais if few disk space is available binaries can be broken. Then one has to check the program files with "file" or "readelf". But how should that help me now?

Is there an easier way to repair the system? Should I continue using prelink afterwards?
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timeBandit · Posted: Sun Oct 29, 2006 1:22 pm Post subject: Re: prelink broke my system

Massimo B. · Posted: Sun Oct 29, 2006 1:32 pm Post subject:

Ok. But which binary could break chroot? I compared the output of file on bash and init binaries of my broken and a stage3 system.

if I could get chroot working I could do an emptyworld emerge from there without copying a stage3 over. Which branches are at least needed for chroot? Then I only copy these over:

/sbin /bin /lib ?
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Massimo B. · Posted: Mon Oct 30, 2006 9:10 am Post subject:

Actually I don't want to renounce prelinking now. Distributions like Mandriva have prelink as cronjob. They wouldn't do if that runs a risk to break the system. As for gentoo my crash must be connected with the explicit rebuild of the 4 ebuild toolchain linux-headers glibc gcc binutils and the following prelink.
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batistuta · Veteran Joined: 29 Jul 2005 Posts: 1384 Location: Aachen

don't mean to stop the party or discourage you. But I've found that prelink didn't do anything at all on my system. And even if KDE took 5 more seconds to load, would that be worth the trouble of prelinking the whole time?

People's experience with prelink has been quite fluctuating. My advice is try it when you have time, but don't kill yourself if it doesn't work or don't have the time to set it up.

Massimo B. · Posted: Mon Oct 30, 2006 10:43 am Post subject:

Hm, setting up doesn't take much time. And a new run is only required for a new kde relase for example. So far I read in the forums also FEATURES="prelink" should work with portage.

Maybe I will exclude some parts from prelink such as the toolchain. Which parts would you recommend to exclude?
Thus only broken bins have to be reemerged.

Having a quite old laptop with 4200rpm drive, KDEs start benefits from prelink.
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batistuta · Veteran Joined: 29 Jul 2005 Posts: 1384 Location: Aachen

I'm not discouring you to try it! I've just meant, to don't panic until you get it working. And be critical when evaluating the improvements. It might pay off, it might not. Make sure to be objective and not just rice

jerry arns · Posted: Sun Dec 03, 2006 6:21 pm Post subject:

Hi,

I have the exatc same problem.

I just ran "prelink -amR". After that all applications gave "segmentation fault".

I rebooted (hard reset) and now at boot time I get:

richfish · Posted: Sun Dec 03, 2006 6:40 pm Post subject:

At this point you'll probably have to boot from a livecd, mount your root filesystem, and reverse the prelinking. Assuming you mount on /mnt/gentoo, you should be able to do:

cd /mnt/gentoo
chroot ./ ./usr/sbin/prelink -au

This is odd, as prelink has never caused any problems on either my x86 or amd64 systems, although I don't use the -m or -R options.

Massimo B. · Posted: Sun Dec 03, 2006 6:47 pm Post subject:

In my case I wasn't able to chroot anymore, but I didn't test to chroot with reverse prelinking as first command (which I neither was aware of that reverse prelinking exists).
Sounds promising, I will remember next time. I only prelink after system backup now.
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jerry arns · Posted: Sun Dec 03, 2006 8:54 pm Post subject:

Thanks for your answer. I tried your suggestion but:

chroot /mnt/gentoo /usr/sbin/prelink -au

doesn't do anything.

chroot /mnt/gentoo /bin/bash

gives segmentation fault.

How did you do, paoleela ?
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Massimo B. · Posted: Sun Dec 03, 2006 9:07 pm Post subject:

I know that seg fault well.
I did one week of emptytree emerge on a stage3 using my old worldfile.
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jerry arns · Posted: Sun Dec 03, 2006 10:23 pm Post subject:

A full re-install is a Zindoz$ solution and I didn't choose Linux to have to do that. Should I have to do that, I'd install MacOSX instead of re-emerging everything (1 hour against 1 week).

Surely only a few binaries need to be replaced, after which I can prelink -au ?

Can I just copy the stage3 tarball, prelink -au and then emerge -e system ?
does the stage 3 tarball contain only system ?
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richfish · Posted: Mon Dec 04, 2006 5:49 am Post subject:

Massimo B. · Posted: Sat Dec 16, 2006 10:17 am Post subject: prelink broke my system again!

Now after the huge crash, I had my system ready again. I did backups now, I tried prelink again.
It broke my system again!

At the moment I'm still inside but can't start any new command. This browser here still works.

Now about your hints and ideas:

jerry arns · Posted: Sat Dec 16, 2006 11:08 am Post subject:

Interesting, my system is also a PPC (iBook).

I booted from a live CD, and copied the stage 3 tarball over my installation. I was then able to boot and issue a prelink -au.

Unfortunatly, this left the system in a state where I could emerge anything, emerge failing at postrm() stage.

After looking around a little bit, I decided to re-install from scratch, saving my /home and /etc.

Emerging the whole thing was done in less than 3 days, and my system is so much faster than before, I just can't believe it. When I upgraded from gcc3 to gcc4, it took more than a day to recompile KDE while during re-install it took less than a night!

Anyway, I didn't tried prelink again, and after what you wrote, I won't!
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Gergan Penkov · Posted: Sat Dec 16, 2006 11:23 am Post subject:

I don't think you need to chroot to unprelink binaries, I would recommend to unprelink directly certain libs and bins - bash, glibc and after that to try to uprelink the whole system.
In fact prelink adds only a section in the binaries, it should be easy to remove it - or have some variable, that prevents the loader from using it

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Massimo B. · Posted: Sat Dec 16, 2006 11:34 am Post subject:

@jerry arns: As for your system speed up, that could just be a *better* fragmentation or better CFLAGS then before. Anyway. As I said a complete reinstall would take me over 1 week. Maybe your iBook is faster. I'm looking for ppc people who are running prelink fine or I will send a ppc bugreport about prelink.

For recovering I did restore /bin /sbin /usr/bin /usr/sbin from backup. # ls command still didn't work. I also had to restore /lib to get ls working. I wasn't aware that prelink also touches libraries?

Now I restore complete /usr for /usr/kde and /usr/qt. I had a static binary of my backup tool dar on the backup medium.

@Gergan Penkov: prelink was the only binary still working. So I tried prelink -au on the running system as I said. Any idea why unprelink failed?
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Gergan Penkov · Posted: Sat Dec 16, 2006 12:05 pm Post subject:

Sorry I didn't look at your last post with the messages, before posting:

Massimo B. · Posted: Sat Dec 16, 2006 12:29 pm Post subject:

Interesting that you call that a serious bug.
Remember, this time I ran prelink it was on completely fresh binaries after the last reinstall.

To avoid fragmentation my reiserfs won't be the best solution but for portage with all the small file it gave me best performance. I'll think about XFS next time since it handles fragmentation better and also has a defrag tool.

I'm not running prelink often after every emerge, only after an kde upgrade. Stable kde doesn't switch anymore that often like it was on earlier gentoo releases. Prelink also has --quick that looks for changed binaries only.

In your last sentence did you mean this?

Gergan Penkov · Posted: Sat Dec 16, 2006 12:44 pm Post subject:

Directly sticking the hidden-flags is not the best idea, as I said most of the pgks, handle this on their own - as I said firefox, openoffice, ffmpeg and such will use it if the configure finds out that you are using recent enough gcc. KDE has the use flag, which is strange as the qt does not have such flag, but will decide on configure

well I called it bug as it seems that it does not generate the needed information to revert the prelink-process and prelink-process seems to be leading to unfunctional system - if this is not a serious bug

_________________
"I knew when an angel whispered into my ear,
You gotta get him away, yeah
Hey little bitch!
Be glad you finally walked away or you may have not lived another day."
Godsmack

Massimo B. · Posted: Sat Dec 16, 2006 1:01 pm Post subject:

First step to a bugreport.
Generally they don't like links to the forums but don't know how to tackle that better.
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Gergan Penkov · Posted: Sat Dec 16, 2006 1:17 pm Post subject:

just reopen the bug with emerge --info, the prelink verson and the messages you receive:)
_________________
"I knew when an angel whispered into my ear,
You gotta get him away, yeah
Hey little bitch!
Be glad you finally walked away or you may have not lived another day."
Godsmack

Massimo B. · Posted: Sat Dec 16, 2006 4:12 pm Post subject:

Good news. sys-devel/prelink-20060712-r1 seems to work.
It brings also a cron script which does fancy things on /etc/prelink.cache. So I trusted the new prelink, configured /etc/conf.d/prelink and started the script manually, I had nothing to loose with my backup.

System is functional. The new prelink should replace the old ebuild (which isn't stable in my eyes).
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Bones McCracker · Veteran Joined: 14 Mar 2006 Posts: 1611 Location: U.S.A.

paoleela,

Prelink-20060712-r1 still working ok for you on ppc?

I see it's still in ~ status and want to check before I do it. It has worked fine for me on x86, but the last time I tried it on ppc it destroyed by system.