Re: 2.25 freeze - a little more than the holiday fortnight to go

[Florian Weimer <fweimer at redhat dot com>]

On 12/21/2016 09:19 PM, Torvald Riegel wrote:
> On Tue, 2016-12-13 at 21:13 +0530, Siddhesh Poyarekar wrote:
> > I had proposed tunables as a blocker for 2.25 during Cauldron and I want
> > to stick with that position unless someone has a good reason to delay it
> > for yet another release.  If there is anything else that needs attention
> > but is not getting it then please ping early and ping often so that it
> > gets the desired attention.
>
> I've added the new condvar and rwlock as blockers.  We've been testing
> them for several weeks in Rawhide and haven't heard any complaints so
> far.  Carlos has reviewed the patches, basically.

The condvar layout change breaks on-disk Berkeley DB database 
environments.  The breakage is persistent across reboots.  Depending on 
the application which uses Berkeley DB, there might not be an easy way 
to recover affected database environments because the usual.

  <https://bugzilla.redhat.com/show_bug.cgi?id=1394862>

This is arguably a bug in Berkeley DB (after a reboot, the first thing 
applications have to do is to reinitialize synchronization objects 
because there definitely are no processes which map the objects left), 
but something we need to solve for Fedora 26 because it affects system 
upgrades.

It does not help that for licensing reasons, we use a quite old version 
of Berkeley DB in Fedora, but other users will be in a similar position 
because the Berkeley DB programming interface changes between releases 
in ways which are not completely source-compatible, so many applications 
cannot upgrade easily, either.

Note that I'm *not* saying we need to fix this in glibc through a compat 
symbol or with the help of flags.  We just need to offer *any* solution 
whatsoever.

Florian