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

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

[Helmut Jarausch]

With glibc-2.27 installed I cannot compile anything, since most  
packages try to include <gnu/stubs-32.h>
which doesn't exit any more.
And downgrading glibc using a binary package doesn't work.

It looks like I have to restore my system from a recent backup,
very annoying!

(I know that glibc-2.27 is masked, but I didn't expect it to be bomb  
like that)
Helmut

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

[Floyd Anderson]

Hi Helmut,

On Fri, 02 Feb 2018 18:34:23 +0100
Helmut Jarausch <jarausch@skynet.be> wrote:
>With glibc-2.27 installed I cannot compile anything, since most 
>packages try to include <gnu/stubs-32.h>
>which doesn't exit any more.
>And downgrading glibc using a binary package doesn't work.
>
>It looks like I have to restore my system from a recent backup,
>very annoying!

Restoring your backup is probably faster but I want to point out the 
possibility of an intermediate build chroot [1] to get back a working 
toolchain. This helped me in the past to solve troubles with glibc and 
when I didn’t knew about buildpkg/buildsyspkg for FEATURES variable. 


Link:
  - [1] <https://wiki.gentoo.org/wiki/Upgrading_Gentoo#Updating_old_systems>


Good luck, bleeding edge(r) and thank you for the warning.


-- 
Regards,
floyd

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

[John Campbell]

On 02/02/2018 01:07 PM, Floyd Anderson wrote:
> Hi Helmut,
> 
> On Fri, 02 Feb 2018 18:34:23 +0100
> Helmut Jarausch <jarausch@skynet.be> wrote:
>> With glibc-2.27 installed I cannot compile anything, since most
>> packages try to include <gnu/stubs-32.h>
>> which doesn't exit any more.
>> And downgrading glibc using a binary package doesn't work.
>>
>> It looks like I have to restore my system from a recent backup,
>> very annoying!
> 
> Restoring your backup is probably faster but I want to point out the
> possibility of an intermediate build chroot [1] to get back a working
> toolchain. This helped me in the past to solve troubles with glibc and
> when I didn’t knew about buildpkg/buildsyspkg for FEATURES variable.

It's been fixed now.  glibc-2.27-r1 is in the tree and re-instates the
x32 libs and headers.

I just emerged the new lib and everything is find.  I have
FEATURES=preserve-libs set so I'm not sure how the missing x32 libs
might effect your compile but I had no issues.

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

[Dale]

John Campbell wrote:
> On 02/02/2018 01:07 PM, Floyd Anderson wrote:
>> Hi Helmut,
>>
>> On Fri, 02 Feb 2018 18:34:23 +0100
>> Helmut Jarausch <jarausch@skynet.be> wrote:
>>> With glibc-2.27 installed I cannot compile anything, since most
>>> packages try to include <gnu/stubs-32.h>
>>> which doesn't exit any more.
>>> And downgrading glibc using a binary package doesn't work.
>>>
>>> It looks like I have to restore my system from a recent backup,
>>> very annoying!
>> Restoring your backup is probably faster but I want to point out the
>> possibility of an intermediate build chroot [1] to get back a working
>> toolchain. This helped me in the past to solve troubles with glibc and
>> when I didn’t knew about buildpkg/buildsyspkg for FEATURES variable.
> It's been fixed now.  glibc-2.27-r1 is in the tree and re-instates the
> x32 libs and headers.
>
> I just emerged the new lib and everything is find.  I have
> FEATURES=preserve-libs set so I'm not sure how the missing x32 libs
> might effect your compile but I had no issues.
>
>
>


While on this topic, I have a question about glibc.  I have it set in
make.conf to save the binary packages.  Generally I use it when I need
to go back shortly after a upgrade, usually Firefox or something. 
However, this package is different since going back a version isn't a
good idea.  My question tho, what if one does go back a version using
those saved binary packages?  Has anyone ever did it and it work or did
it and it fail miserably? 

While at it, if a upgrade really breaks a system, what is the *correct*
thing to do?  Wait for a new fixed version, even if it breaks things in
the meantime?  Just curious. 

Thanks to the OP for the heads up.  I run stable on that BUT it's still
a good idea to warn others, who may not run stable and not know the
problem, yet. 

Dale

:-)  :-) 

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

[Nikos Chantziaras]

On 03/02/18 07:54, Dale wrote:
> While on this topic, I have a question about glibc.  I have it set in
> make.conf to save the binary packages.  Generally I use it when I need
> to go back shortly after a upgrade, usually Firefox or something.
> However, this package is different since going back a version isn't a
> good idea.  My question tho, what if one does go back a version using
> those saved binary packages?  Has anyone ever did it and it work or did
> it and it fail miserably?

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.

This whole thing is not actually special to glibc. Other libraries work 
in a similar manner. You can't just link other software against a new 
version of the library, then remove the library and replace it with an 
older one. It might result in breakage. But glibc is used by almost 
everything, it's not "just a library", it is *the* library, and so it 
has a special protection to prevent a downgrade. You can bypass that 
protection and downgrade anyway, but then you need to know what you're 
doing and how to restore your system correctly. If any sys-devel 
packages are affected, you might not be able to do it. If only end-user 
packages are affected which are not used during an emerge, then it's 
quite safe to downgrade.

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

[Dale]

Nikos Chantziaras wrote:
> On 03/02/18 07:54, Dale wrote:
>> While on this topic, I have a question about glibc.  I have it set in
>> make.conf to save the binary packages.  Generally I use it when I need
>> to go back shortly after a upgrade, usually Firefox or something.
>> However, this package is different since going back a version isn't a
>> good idea.  My question tho, what if one does go back a version using
>> those saved binary packages?  Has anyone ever did it and it work or did
>> it and it fail miserably?
>
> 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.
>
> This whole thing is not actually special to glibc. Other libraries
> work in a similar manner. You can't just link other software against a
> new version of the library, then remove the library and replace it
> with an older one. It might result in breakage. But glibc is used by
> almost everything, it's not "just a library", it is *the* library, and
> so it has a special protection to prevent a downgrade. You can bypass
> that protection and downgrade anyway, but then you need to know what
> you're doing and how to restore your system correctly. If any
> sys-devel packages are affected, you might not be able to do it. If
> only end-user packages are affected which are not used during an
> emerge, then it's quite safe to downgrade.
>
>
>

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. 

I wonder, is this sort of info on Gentoo's wiki?  If not, shouldn't it
be?  I've always read that downgrading is a bad idea and strongly
discouraged but if one runs unstable on a regular basis or just hits
that random corner case bug, one may run into this even if one doesn't
have the experience to know how to put the broken pieces back together
again. 

Thanks for the info.  At least there is a option, even if it might get
interesting.  ;-)

Dale

:-)  :-) 

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

[Nikos Chantziaras]

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.

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

[Dale]

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

:-)  :-) 

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

[Helmut Jarausch]

On 02/03/2018 06:54:06 AM, Dale wrote:
> While on this topic, I have a question about glibc.  I have it set in
> make.conf to save the binary packages.  Generally I use it when I need
> to go back shortly after a upgrade, usually Firefox or something. 
> However, this package is different since going back a version isn't a
> good idea.  My question tho, what if one does go back a version using
> those saved binary packages?  Has anyone ever did it and it work or  
> did
> it and it fail miserably? 
> 
I've tried to binary emerge my previous version. This didn't succeed  
since
the ebuild disallows downgrading glibc.

Luckily I had backuped my system just 20 hours ago.

Does anybody know how to restore ONLY those files which are
more recent on the target file system.
(My whole back is 124 Gb large which is a lot to copy back)

Many thanks for a hint,
Helmut

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

[Marc Joliet]

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Am Samstag, 3. Februar 2018, 10:50:53 CET schrieb Helmut Jarausch:
> On 02/03/2018 06:54:06 AM, Dale wrote:
> > While on this topic, I have a question about glibc.  I have it set in
> > make.conf to save the binary packages.  Generally I use it when I need
> > to go back shortly after a upgrade, usually Firefox or something. 
> > However, this package is different since going back a version isn't a
> > good idea.  My question tho, what if one does go back a version using
> > those saved binary packages?  Has anyone ever did it and it work or
> > did
> > it and it fail miserably? 
> 
> I've tried to binary emerge my previous version. This didn't succeed
> since
> the ebuild disallows downgrading glibc.
> 
> Luckily I had backuped my system just 20 hours ago.

Having up-to-date backups is always good :) .

> Does anybody know how to restore ONLY those files which are
> more recent on the target file system.
> (My whole back is 124 Gb large which is a lot to copy back)

If you can access the backups like a normal file system, then using rsync with 
the --update option looks to me like what you want:

"-u, --update                skip files that are newer on the receiver".

> Many thanks for a hint,
> Helmut

HTH
-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup

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

[Helmut Jarausch]

On 02/03/2018 04:11:33 PM, Marc Joliet wrote:
> Am Samstag, 3. Februar 2018, 10:50:53 CET schrieb Helmut Jarausch:
> > On 02/03/2018 06:54:06 AM, Dale wrote:
> > > While on this topic, I have a question about glibc.  I have it  
> set in
> > > make.conf to save the binary packages.  Generally I use it when I  
> need
> > > to go back shortly after a upgrade, usually Firefox or something.
> > > However, this package is different since going back a version  
> isn't a
> > > good idea.  My question tho, what if one does go back a version  
> using
> > > those saved binary packages?  Has anyone ever did it and it work  
> or
> > > did
> > > it and it fail miserably?
> >
> > I've tried to binary emerge my previous version. This didn't succeed
> > since
> > the ebuild disallows downgrading glibc.
> >
> > Luckily I had backuped my system just 20 hours ago.
> 
> Having up-to-date backups is always good :) .
> 
> > Does anybody know how to restore ONLY those files which are
> > more recent on the target file system.
> > (My whole back is 124 Gb large which is a lot to copy back)
> 
> If you can access the backups like a normal file system, then using  
> rsync with
> the --update option looks to me like what you want:
> 
> "-u, --update                skip files that are newer on the  
> receiver".
> 

High Marc,
I think I need the opposite :
   only update files which are newer on the receiver

Thanks,
Helmut

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

[Marc Joliet]

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Am Samstag, 3. Februar 2018, 18:34:11 CET schrieb Helmut Jarausch:
> On 02/03/2018 04:11:33 PM, Marc Joliet wrote:
> > Am Samstag, 3. Februar 2018, 10:50:53 CET schrieb Helmut Jarausch:
> > > On 02/03/2018 06:54:06 AM, Dale wrote:
> > > > While on this topic, I have a question about glibc.  I have it
> > 
> > set in
> > 
> > > > make.conf to save the binary packages.  Generally I use it when I
> > 
> > need
> > 
> > > > to go back shortly after a upgrade, usually Firefox or something.
> > > > However, this package is different since going back a version
> > 
> > isn't a
> > 
> > > > good idea.  My question tho, what if one does go back a version
> > 
> > using
> > 
> > > > those saved binary packages?  Has anyone ever did it and it work
> > 
> > or
> > 
> > > > did
> > > > it and it fail miserably?
> > > 
> > > I've tried to binary emerge my previous version. This didn't succeed
> > > since
> > > the ebuild disallows downgrading glibc.
> > > 
> > > Luckily I had backuped my system just 20 hours ago.
> > 
> > Having up-to-date backups is always good :) .
> > 
> > > Does anybody know how to restore ONLY those files which are
> > > more recent on the target file system.
> > > (My whole back is 124 Gb large which is a lot to copy back)
> > 
> > If you can access the backups like a normal file system, then using
> > rsync with
> > the --update option looks to me like what you want:
> > 
> > "-u, --update                skip files that are newer on the
> > receiver".
> 
> High Marc,
> I think I need the opposite :
>    only update files which are newer on the receiver

Ah, sorry, I misread that (in your case it wouldn't make any sense, either).  
Although in that case, shouldn't normal rsync do what you want?  It won't 
update files that haven't changed since the backup (determined by default by 
comparing file size and mtime, see rsync(1)).

> Thanks,
> Helmut

HTH
-- 
Marc Joliet
--
"People who think they know everything really annoy those of us who know we
don't" - Bjarne Stroustrup

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

[Bill Kenworthy]

On 04/02/18 01:34, Helmut Jarausch wrote:
> On 02/03/2018 04:11:33 PM, Marc Joliet wrote:
>> Am Samstag, 3. Februar 2018, 10:50:53 CET schrieb Helmut Jarausch:
>> > On 02/03/2018 06:54:06 AM, Dale wrote:
>> > > While on this topic, I have a question about glibc.  I have it set in
>> > > make.conf to save the binary packages.  Generally I use it when I
>> need
>> > > to go back shortly after a upgrade, usually Firefox or something.
>> > > However, this package is different since going back a version isn't a
>> > > good idea.  My question tho, what if one does go back a version using
>> > > those saved binary packages?  Has anyone ever did it and it work or
>> > > did

1. do another backup
2. take your last good binary package and unpack it in the root
directory - it is an "image" of that package as it sits in the file system.
3. rebuild that version of glibc by overiding emerge - comment out "die
"aborting to save your system" in /usr/portage/eclass/toolchain-glibc.eclass

I have done this a couple of times with gcc (when manual deletes have
gone rogue) but it should work with glibc as you have not recompiled any
new packages.

BillK

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

[Helmut Jarausch]

On 02/04/2018 12:21:13 AM, Bill Kenworthy wrote:
> On 04/02/18 01:34, Helmut Jarausch wrote:
> > On 02/03/2018 04:11:33 PM, Marc Joliet wrote:
> >> Am Samstag, 3. Februar 2018, 10:50:53 CET schrieb Helmut Jarausch:
> >> > On 02/03/2018 06:54:06 AM, Dale wrote:
> >> > > While on this topic, I have a question about glibc.  I have it  
> set in
> >> > > make.conf to save the binary packages.  Generally I use it  
> when I
> >> need
> >> > > to go back shortly after a upgrade, usually Firefox or  
> something.
> >> > > However, this package is different since going back a version  
> isn't a
> >> > > good idea.  My question tho, what if one does go back a  
> version using
> >> > > those saved binary packages?  Has anyone ever did it and it  
> work or
> >> > > did
> 
> 1. do another backup
> 2. take your last good binary package and unpack it in the root
> directory - it is an "image" of that package as it sits in the file  
> system.
> 3. rebuild that version of glibc by overiding emerge - comment out  
> "die
> "aborting to save your system" in  
> /usr/portage/eclass/toolchain-glibc.eclass
> 
> I have done this a couple of times with gcc (when manual deletes have
> gone rogue) but it should work with glibc as you have not recompiled  
> any
> new packages.
> 

Many thanks Bil,
Helmut

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

[Neil Bothwick]

On 3 February 2018 17:34:11 GMT, Helmut Jarausch <jarausch@skynet.be> wrote:
>On 02/03/2018 04:11:33 PM, Marc Joliet wrote:
>> Am Samstag, 3. Februar 2018, 10:50:53 CET schrieb Helmut Jarausch:
>> > On 02/03/2018 06:54:06 AM, Dale wrote:
>> > > While on this topic, I have a question about glibc.  I have it  
>> set in
>> > > make.conf to save the binary packages.  Generally I use it when I
> 
>> need
>> > > to go back shortly after a upgrade, usually Firefox or something.
>> > > However, this package is different since going back a version  
>> isn't a
>> > > good idea.  My question tho, what if one does go back a version  
>> using
>> > > those saved binary packages?  Has anyone ever did it and it work 
>
>> or
>> > > did
>> > > it and it fail miserably?
>> >
>> > I've tried to binary emerge my previous version. This didn't
>succeed
>> > since
>> > the ebuild disallows downgrading glibc.
>> >
>> > Luckily I had backuped my system just 20 hours ago.
>> 
>> Having up-to-date backups is always good :) .
>> 
>> > Does anybody know how to restore ONLY those files which are
>> > more recent on the target file system.
>> > (My whole back is 124 Gb large which is a lot to copy back)
>> 
>> If you can access the backups like a normal file system, then using  
>> rsync with
>> the --update option looks to me like what you want:
>> 
>> "-u, --update                skip files that are newer on the  
>> receiver".
>> 
>
>High Marc,
>I think I need the opposite :
>   only update files which are newer on the receiver
>
>Thanks,
>Helmut

Run the rsync in the opposite direction with - n as well as - u. That should give you a list of files that are newer on the live system. 
-- 
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