[Samba] WORKAROUND: Re: [samba4] crash of winbind after "ls -l /usr/local/samba/var/locks/sysvol"

[Andrew Bartlett]

On Mon, 2013-06-17 at 11:51 -0700, Jeremy Allison wrote:
> On Sat, Jun 15, 2013 at 06:35:34PM +1000, Andrew Bartlett wrote:
> > On Tue, 2013-04-30 at 20:32 +0000, Philippe.Simonet at swisscom.com wrote:
> > > Many thanks Michae for your answer,l
> > > 
> > > here the results of bisect and some samba 'strange' console output.
> > > 
> > > I hope this can help
> > > 
> > > best regards
> > > 
> > > Philippe
> > > 
> > > 
> > > -----------------------------------------------------------------------------------------------------
> > > to produce the problem : 
> > > -----------------------------------------------------------------------------------------------------
> > > ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var --enable-fhs
> > > make install
> > > samba -i -M single
> > > wbinfo --uid-info 3000000
> > > 
> > > -----------------------------------------------------------------------------------------------------
> > > last bisect : 
> > > -----------------------------------------------------------------------------------------------------
> > > git bisect good
> > > f77d5d6479c879c8770fbc9a6ca5656ef3e41019 is the first bad commit
> > > commit f77d5d6479c879c8770fbc9a6ca5656ef3e41019
> > > Author: Timur Bakeyev <timur at FreeBSD.org>
> > > Date:   Wed Feb 27 16:25:07 2013 -0800
> > > 
> > >     Fix bug # 9666 - Broken filtering of link-local addresses.
> > >     
> > >     This patch should address the problem with Link Local addresses
> > >     on FreeBSD and Linux.
> > >     
> > >     Reviewed-by: Jeremy Allison <jra at samba.org>
> > >     
> > >     Autobuild-User(v4-0-test): Karolin Seeger <kseeger at samba.org>
> > >     Autobuild-Date(v4-0-test): Fri Mar  1 18:21:19 CET 2013 on sn-devel-104
> > > 
> > > :040000 040000 e022079ce7298f5cfa9d99e51e7afedb35048b02 164c1aba0559999b0179d3b47f415f6e3e5b3cd7 M      lib
> > > -----------------------------------------------------------------------------------------------------
> > 
> > First, I do apologise for the entirely unacceptable delay in dealing
> > with this issue.  I've CC'ed the developers involved in that patch, in
> > the hope that they might be able to investigate it.
> > 
> > It certainly looks like this is a valid bisect, because when I set:
> > 	interfaces = virbr0:0 lo 
> > 	bind interfaces only = yes
> > 
> > in the smb.conf the crash isn't reproduced, but when I comment this out,
> > it crashes right away. 
> > 
> > I'll continue to look into this myself, as well as following up with
> > those involved in the change, but I wanted to give you a big thankyou
> > for doing the bisect, and to say that you clearly are on the right
> > track. 
> 
> Hmmm. Very strange ! That change prevents link-local and IPv4-compat
> addresses being returned in our interface list, otherwise it should
> have no effect...
> 
> What is the stack backtrace from the crash ?

It's very odd, and looks like one of those 'butterfly changing the
course of a hurricane' kind of things.
https://bugzilla.samba.org/show_bug.cgi?id=9820 has some more details,
including valgrind work, and attempts to patch it in other ways, but I'm
still quite puzzled as so how this patch fits into it.

This is the #1 crash folks are reporting on the AD DC.

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org