Ticket #235 (closed defect: fixed)

Opened 15 years ago

Last modified 15 years ago

Debathena Live CD installs an initrd that enables compcache.

Reported by: xavid Owned by: xavid
Priority: normal Milestone: Summer 2009 Deployment
Component: livecd Keywords:
Cc: Fixed in version:
Upstream bug:


   debathena / livecd / xavid  19:54  ('I want to be the duke of Chicago.`)
       Jaunty-compatible live cd is pushed and ready for someone to prod on 
       debuild.  If someone other than me wants to try the
       less-trusted-version, http://debathena-livecd-build.xvm/cds/
   debathena / livecd / xavid  19:59  ('Sucks-to-be-you-tastic.`)
       I guess I'll send mail if no one's particularly up for prodding it now.
   debathena / livecd / andersk  16:53  (Anders Kaseorg)
       debathena-livecd-convert runs `update-initramfs -u` from inside the
       live CD chroot.  As it turns out, this results in machines installed
       using the live CD, such as ozok-the-destroyer.mit.edu, to be fuxx0red
       in various ways (e.g. compcache is enabled).
   debathena / livecd / broder  16:54  (Evan Broder)
       Can you put this on the existing Live CD bug, or open a new one?
   debathena / livecd / jdreed  16:54  (This zephyr does not necessarily reflect
       A new one, please.  The existing one is a bit too general
   debathena / livecd.d / jdreed  16:55  (This zephyr does not necessarily refle
       I blame the person who opened the ticket for not picking a better
       subject line
   debathena / livecd.d / broder  16:55  (Evan Broder)
   debathena / livecd / xavid  16:56  (“Werewolves stash their car keys. You don
       Is that called in the postinst of new kernels?
   debathena / livecd / andersk  16:56  (Anders Kaseorg)
       Yes, but you also call it explicitly.
   debathena / livecd / xavid  16:57  ("Never bite a gift horse in the neck.")
       Right, but I only started doing that a few days ago, and I didn't think
       ozok had been reinstalled in that time.
   debathena / livecd / ezyang  16:57  (Edward Z. Yang)
       Ozok was reinstalled on April 12th
   debathena / livecd / xavid  16:58  ('Do rocks chew their cud?')
       (Previously, the live CD would just be totally broken if there didn't
       exist a more recent kernel to upgrade to at build time.)
   debathena / livecd.d / jdreed  17:00  (This zephyr does not necessarily refle
       Is the LiveCD still a manual build process?  Weren't we going to do
       something about that?
   debathena / livecd / xavid  17:00  ('Look!  It's really happy!  And by happy,
       I can replace the explicit one with a call to mkinitramfs, but getting
       the postinst to DTRT will be more difficult.
   debathena / livecd / andersk  17:00  (Anders Kaseorg)
       Well, how do the Ubuntu guys do it?
   debathena / livecd.d / xavid  17:01  ('Sucks-to-be-you-tastic.`)
       The Live CD is automated but still has to be run manually, mostly
       because we're not past the point where we need to manually test each
       new iso
   debathena / livecd / xavid  17:02  (“Can vampires suck blood from rocks?”)
       No idea?  My main reference for this has been
       https://help.ubuntu.com/community/LiveCDCustomization, which doesn't
       mention this issue.
   debathena / livecd / andersk  17:05  (Anders Kaseorg)
       Hmm, is the official CD’s casper/initrd.gz different from the
       /boot/initrd.img-2.6.27-11-generic in the filesystem image?
   debathena / livecd / xavid  17:05  ("Never bite a gift horse in the neck.")
       I assume so.
   debathena / livecd / xavid  17:08  ('Sucks-to-be-you-tastic.`)
       (Based on this new information; before I'd assumed they were the same.)
   debathena / livecd / andersk  17:10  (Anders Kaseorg)
       Have you looked at
       https://help.ubuntu.com/community/LiveCDCustomizationFromScratch ?
   debathena / livecd / xavid  17:18  (“I like horse-molesting monkeys.”)
       Hmm; that's worth looking at.
   debathena / livecd / xavid  17:25  (“Where does the scary glowing man eat the
       Though, it looks like in those instructions it also uses the
       initramfs generated by installing a kernel, and has the same initrd in
       both the actual /boot and the outer /casper, so that doesn't address
   debathena / livecd / xavid  17:25  (“Welcome back cybergirls! and you—honorar
       What are the symptoms of compcache being enabled?  Are you certain that
       normal Ubuntus installed from a Live CD don't have it enabled?
   debathena / livecd / ezyang  17:26  (Edward Z. Yang)
       The easiest way to check is lsmod | grep compcache
   debathena / livecd / ezyang  17:26  (Edward Z. Yang)
       One important side-effect is that ramzswap is registered as swap
   debathena / livecd / ezyang  17:27  (Edward Z. Yang)
       I know fo sho that it isn't default, since we've had multiple confirm
       that, while they have the compcache kernel module, it was not active
   debathena / livecd / xavid  17:27  ('Can you guys tell me at wrapup if I’m th
       Hmm... well, I'll investigate more when I'm at a VMware and less
   debathena / livecd / ezyang  17:28  (Edward Z. Yang)
       Sounds good.
   debathena / livecd / xavid  17:28  (“There’s nothing that says we can’t have 
       I certainly don't do anything that would affect that directly.
   debathena / livecd / andersk  17:34  (Anders Kaseorg)
       compcache gets enabled if you boot with an initrd that was generated  
       on a system with the casper package installed.
   debathena / livecd / andersk  17:35  (Anders Kaseorg)
       > One important side-effect is that ramzswap is registered as swap
       (This is, in fact, entirely the point, not a side effect.)
   debathena / livecd / ezyang  17:35  (Edward Z. Yang)
       sure :-)
   debathena / livecd / xavid  17:42  ("Angry people are always cooler when they
       Ok, that should be easy enough to work around, then.

Change History

comment:1 Changed 15 years ago by xavid

  • Status changed from new to accepted

comment:2 Changed 15 years ago by andersk

Also the installed system somehow ends up with the casper package installed, which causes compcache to be enabled in every generated initramfs.

comment:3 Changed 15 years ago by xavid

I'm not sure why that would happen on this Live CD but not upstream, since the casper package is installed in the CD root upstream. I can add a hack to remove it on install if necessary, though. "After May 22nd."

comment:4 Changed 15 years ago by xavid

  • Status changed from accepted to proposed

I believe that my uninstall-casper-in-the-success-command hack should be sufficient to solve this problem. I'm mystified why this doesn't happen upstream but happens here, but whatever. I haven't tested this extensively yet because I got mauled by Java, though.

(I'm using -proposed loosely.

comment:5 Changed 15 years ago by geofft

  • Status changed from proposed to closed
  • Resolution set to fixed

I've uploaded the live CD with these fixes to /mit/debathena/live and re-signed that directory with the archive signing key. Xavid's tested, though I haven't.

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