[Techtalk] Bug when upgrading glibc @ RH8

Maria Blackmore mariab at cats.meow.at
Fri Mar 21 16:36:07 EST 2003


On Fri, 21 Mar 2003, Magni Onsoien wrote:

> Just wanted to share a not-very-funny-bug with you...

I'm very sorry to say it, but this isn't a bug.

<snip>

> There is a bug in the latest glibc-errata for RedHat 8,
> RHSA-2003:089-08, glibc-2.3.2-4.80, breaking sshd and probably also
> sendmail and postfix (or some other part of our mailsystem).

This is to be expected when you update libraries and change their
revisions - anything still expecting to find the old versions of the
libraries will break in interesting and exotic ways.

> The fix is to restart the service

<advocacy type="debian">
apt does this for you, under debian :)
</advocacy type="debian">

> but unless you remained logged in after updating glibc

Which imho you probably ought to after upgrading something as major as
glibc, which has the ability to break just about every single thing on
the machine :)

When updating major libraries, it's also wise to have a set of statically
compiled utilities, busybox is useful for this.

> (I don't _think_ the ssh-connections died after the update)

They wouldn't have, no.

You can restart the sshd without interrupting currently running sessions,
and can also test sshd works ok by starting it on a different port with
sshd -p 2222 (for example)

> you'll either need physical access to the server to do
> that, or you need to be able to do it remote.

Serial consoles are very useful :)

have a look at the range that cyclades do, for example, they're to be
recommended

> So those of you running RedHat 8: don't update the glibc-package unless
> you are able - and prepared - to restart a lot of services manually 
> afterwards...

This goes for all distributions.
Things breaking after you upgrade glibc (or any major set of libraries) is
to be expected, and indeed comes under Things That Are Supposed To Happen
#973

> (I expect RedHat to come with a new update soon, at least one with a
> warning about what will break if they can't fix this otherwise.)

I imagine that since this is unavoidable, the most they would do is a
warning to make sure you restart programs that are running so that they
use the new glibc.

For some people it would be simpler to reboot. Indeed, if you're expecting
something to go wrong, you can start a shutdown with a 10 minute or 15
minute warning, do the update, and then cancel the shutdown when you're
sure that everything went ok.  If it doesn't go ok, then you can be
reasonably assured that the machine will shutdown and reboot (of course
this could be a bad thing if the machine is left in a broken state, yay
for busybox :)

have fun :)

Maria



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