Re: [gentoo-user] Re: Heads Up - glibc-2.27 breaks my system

[Dale <rdalek1967@gmail.com>]

Nikos Chantziaras wrote:
> On 03/02/18 16:08, Dale wrote:
>> Nikos Chantziaras wrote:
>>> It is perfectly fine to downgrade glibc if you didn't emerge anything
>>> that compiled binaries.
>>>
>>> If you did, you can still downgrade, but then you need to rebuild the
>>> packages that you emerged since the glibc upgrade. qlop is your friend
>>> here; it lets you find out the dates on which you emerged packages.
>>
>> That makes sense.  So, if worse comes to worse, downgrade, then emerge
>> -e world if unsure what all has been updated since.  If, using qlop or
>> friends, you can figure what was done since the upgrade, emerge those to
>> make sure the linking is correct.  At least that is a option that should
>> be doable.  That's better than thinking you can't downgrade for any
>> reason, period.
>
> You might not be able to do that, if python (used by emerge) uses
> something that breaks when downgrading glibc. Or gcc. Or binutils. Or
> bash. Or anything else that's needed during an emerge.
>
> So you need to check with qlop *before* downgrading, and if it looks
> like something critical was built against the new glibc, then all bets
> are off. Which is why the downgrade protection exists in the first place.
>
> The only way out of this, is restoring from backup or fixing things by
> booting from a sysrescuecd or similar.
>
> If only firefox or your media player and stuff like that got built
> against the new glibc, then it's fine to downgrade. Otherwise, you
> could end up bricking your system.
>
>
>


I see.  That would cause problems.  Depending on how bad it is affected,
even emerge -k may not work same could be said for tar to I guess.  So,
while upgrading glibc is required, eventually, it is also risky unless
it is well, very well, tested. 

I searched the wiki, I don't see anything about this topic.  I don't
know how to do the wiki thing but it would be nice for someone who does
to create a wiki page for this.  It is likely a rare thing to happen but
the consequences of it are pretty serious and tricky to fix.  To keep
from hijacking this thread anymore, I'd be happy to start a new thread,
let people post what they know and should be on the wiki and then
whoever knows how to do a wiki page move whatever is agreed on to the
page. 

Any takers? 

Dale

:-)  :-)